clonebundles: stop shell quoting `HGCB_BUNDLE_BASENAME` environment variable

This causes problems in `test-clonebundles-autogen.t` on Windows, because the
quoted path ends up being passed to the `cp` command, which fails, because quote
characters are not a legal part of a file name.  I don't see any quoting in
environment variables on either MSYS or WSL, even with weird ones that appear to
have escape sequences like `PS1=\[\033]0;$MSYSTEM:\w\007` (in MSYS).  The
quoting was added back in 5ae30ff79c76, and as shown here, was causing problems
even on posix when a quote was slipped into the path.

(The other obvious problem is that the command is spun up shell style, which
invokes `cmd.exe`, which doesn't know about `$foo` style variables.  That will
be addressed next, but that change didn't work without this too.)

hgext/clonebundles.py

@@ -786,9 +786,8 def upload_bundle(repo, bundle):
     else:
         cmd = repo.ui.config(b'clone-bundles', b'upload-command')
         url = repo.ui.config(b'clone-bundles', b'url-template')
-        filepath = procutil.shellquote(bundle.filepath)
         variables = {
-            b'HGCB_BUNDLE_PATH': filepath,
+            b'HGCB_BUNDLE_PATH': bundle.filepath,
             b'HGCB_BUNDLE_BASENAME': basename,
         }
         env = procutil.shellenviron(environ=variables)

tests/test-clonebundles-autogen.t

@@ -76,8 +76,6 Test that the HGCB_BUNDLE_BASENAME varia
   adding manifests
   adding file changes
   2 changesets found
-  cp: cannot stat ''\''$TESTTMP/embed-"-name/server/.hg/tmp-bundles/full-bzip2-v2-2_revs-aaff8d2ffbbf_tip-*_txn.hg'\''': $ENOENT$ (glob)
-  abort: command returned status 1: cp "$HGCB_BUNDLE_PATH" "$TESTTMP"/final-upload/
   added 2 changesets with 2 changes to 2 files
   clone-bundles: starting bundle generation: bzip2-v2