packaging: Clean up call to read the version

There is no need to wrap it in a string, we can call it directly.

default.nix

@@ -1,217 +1,217 b''
 # Nix environment for the community edition
 #
 # This shall be as lean as possible, just producing the Enterprise
 # derivation. For advanced tweaks to pimp up the development environment we use
 # "shell.nix" so that it does not have to clutter this file.
 
 { pkgs ? (import <nixpkgs> {})
 , pythonPackages ? "python27Packages"
 , pythonExternalOverrides ? self: super: {}
 , doCheck ? true
 }:
 
 let pkgs_ = pkgs; in
 
 let
   pkgs = pkgs_.overridePackages (self: super: {
     # Override subversion derivation to
     #  - activate python bindings
     #  - set version to 1.8
     subversion = super.subversion18.override {
        httpSupport = true;
        pythonBindings = true;
        python = self.python27Packages.python;
     };
   });
 
   inherit (pkgs.lib) fix extends;
 
   basePythonPackages = with builtins; if isAttrs pythonPackages
     then pythonPackages
     else getAttr pythonPackages pkgs;
 
   elem = builtins.elem;
   basename = path: with pkgs.lib; last (splitString "/" path);
   startsWith = prefix: full: let
     actualPrefix = builtins.substring 0 (builtins.stringLength prefix) full;
   in actualPrefix == prefix;
 
   src-filter = path: type: with pkgs.lib;
     let
       ext = last (splitString "." path);
     in
       !elem (basename path) [
         ".git" ".hg" "__pycache__" ".eggs" "node_modules"
         "build" "data" "tmp"] &&
       !elem ext ["egg-info" "pyc"] &&
       !startsWith "result" path;
 
   rhodecode-enterprise-ce-src = builtins.filterSource src-filter ./.;
 
   # Load the generated node packages
   nodePackages = pkgs.callPackage "${pkgs.path}/pkgs/top-level/node-packages.nix" rec {
     self = nodePackages;
     generated = pkgs.callPackage ./pkgs/node-packages.nix { inherit self; };
   };
 
   # TODO: Should be taken automatically out of the generates packages.
   # apps.nix has one solution for this, although I'd prefer to have the deps
   # from package.json mapped in here.
   nodeDependencies = with nodePackages; [
     grunt
     grunt-contrib-concat
     grunt-contrib-jshint
     grunt-contrib-less
     grunt-contrib-watch
     jshint
   ];
 
   pythonGeneratedPackages = self: basePythonPackages.override (a: {
     inherit self;
   })
   // (scopedImport {
     self = self;
     super = basePythonPackages;
     inherit pkgs;
     inherit (pkgs) fetchurl fetchgit;
   } ./pkgs/python-packages.nix);
 
   pythonOverrides = import ./pkgs/python-packages-overrides.nix {
     inherit
       basePythonPackages
       pkgs;
   };
 
   pythonLocalOverrides = self: super: {
     rhodecode-enterprise-ce =
       let
-        version = "${builtins.readFile ./rhodecode/VERSION}";
+        version = builtins.readFile ./rhodecode/VERSION;
         linkNodeModules = ''
           echo "Link node packages"
           # TODO: check if this adds stuff as a dependency, closure size
           rm -fr node_modules
           mkdir -p node_modules
           ${pkgs.lib.concatMapStrings (dep: ''
             ln -sfv ${dep}/lib/node_modules/${dep.pkgName} node_modules/
           '') nodeDependencies}
           echo "DONE: Link node packages"
         '';
       in super.rhodecode-enterprise-ce.override (attrs: {
 
       inherit doCheck;
       name = "rhodecode-enterprise-ce-${version}";
       version = version;
       src = rhodecode-enterprise-ce-src;
 
       buildInputs =
         attrs.buildInputs ++
         (with self; [
           pkgs.nodePackages.grunt-cli
           pkgs.subversion
           pytest-catchlog
           rc_testdata
         ]);
 
       propagatedBuildInputs = attrs.propagatedBuildInputs ++ (with self; [
         rhodecode-tools
       ]);
 
       # TODO: johbo: Make a nicer way to expose the parts. Maybe
       # pkgs/default.nix?
       passthru = {
         inherit
           pythonLocalOverrides
           myPythonPackagesUnfix;
         pythonPackages = self;
       };
 
       LC_ALL = "en_US.UTF-8";
       LOCALE_ARCHIVE =
         if pkgs.stdenv ? glibc
         then "${pkgs.glibcLocales}/lib/locale/locale-archive"
         else "";
 
       # Somewhat snappier setup of the development environment
       # TODO: move into shell.nix
       # TODO: think of supporting a stable path again, so that multiple shells
       #       can share it.
       shellHook = ''
         tmp_path=$(mktemp -d)
         export PATH="$tmp_path/bin:$PATH"
         export PYTHONPATH="$tmp_path/${self.python.sitePackages}:$PYTHONPATH"
         mkdir -p $tmp_path/${self.python.sitePackages}
         python setup.py develop --prefix $tmp_path --allow-hosts ""
       '' + linkNodeModules;
 
       preCheck = ''
         export PATH="$out/bin:$PATH"
       '';
 
       postCheck = ''
         rm -rf $out/lib/${self.python.libPrefix}/site-packages/pytest_pylons
         rm -rf $out/lib/${self.python.libPrefix}/site-packages/rhodecode/tests
       '';
 
       preBuild = linkNodeModules + ''
         grunt
         rm -fr node_modules
       '';
 
       postInstall = ''
         # python based programs need to be wrapped
         ln -s ${self.supervisor}/bin/supervisor* $out/bin/
         ln -s ${self.gunicorn}/bin/gunicorn $out/bin/
         ln -s ${self.PasteScript}/bin/paster $out/bin/
 
         # rhodecode-tools
         # TODO: johbo: re-think this. Do the tools import anything from enterprise?
         ln -s ${self.rhodecode-tools}/bin/rhodecode-* $out/bin/
 
         # note that condition should be restricted when adding further tools
         for file in $out/bin/*; do  #*/
           wrapProgram $file \
               --prefix PYTHONPATH : $PYTHONPATH \
               --set PYTHONHASHSEED random
         done
 
         mkdir $out/etc
         cp configs/production.ini $out/etc
 
         echo "Writing meta information for rccontrol to nix-support/rccontrol"
         mkdir -p $out/nix-support/rccontrol
         cp -v rhodecode/VERSION $out/nix-support/rccontrol/version
         echo "DONE: Meta information for rccontrol written"
 
         # TODO: johbo: Make part of ac-tests
         if [ ! -f rhodecode/public/js/scripts.js ]; then
           echo "Missing scripts.js"
           exit 1
         fi
         if [ ! -f rhodecode/public/css/style.css ]; then
           echo "Missing style.css"
           exit 1
         fi
       '';
 
     });
 
     rc_testdata = self.buildPythonPackage rec {
       name = "rc_testdata-0.7.0";
       src = pkgs.fetchhg {
         url = "https://code.rhodecode.com/upstream/rc_testdata";
         rev = "v0.7.0";
         sha256 = "0w3z0zn8lagr707v67lgys23sl6pbi4xg7pfvdbw58h3q384h6rx";
       };
     };
 
   };
 
   # Apply all overrides and fix the final package set
   myPythonPackagesUnfix =
     (extends pythonExternalOverrides
     (extends pythonLocalOverrides
     (extends pythonOverrides
              pythonGeneratedPackages)));
   myPythonPackages = (fix myPythonPackagesUnfix);
 
 in myPythonPackages.rhodecode-enterprise-ce