nix: Add subprocess32 to build inputs.

From the python 2 docs: POSIX users (Linux, BSD, etc.)
are strongly encouraged to install and use the much
more recent subprocess32 module instead of the version
included with python 2.7. It is a drop in replacement
with better behavior in many situations.

pkgs/python-packages.nix

@@ -1384,7 +1384,7 b''
     name = "rhodecode-enterprise-ce-4.5.0";
     buildInputs = with self; [WebTest configobj cssselect lxml mock pytest pytest-cov pytest-runner pytest-sugar];
     doCheck = true;
-    propagatedBuildInputs = with self; [Babel Beaker FormEncode Mako Markdown MarkupSafe MySQL-python Paste PasteDeploy PasteScript Pygments Pylons Pyro4 Routes SQLAlchemy Tempita URLObject WebError WebHelpers WebHelpers2 WebOb WebTest Whoosh alembic amqplib anyjson appenlight-client authomatic backport-ipaddress celery channelstream colander decorator deform docutils gevent gunicorn infrae.cache ipython iso8601 kombu msgpack-python packaging psycopg2 py-gfm pycrypto pycurl pyparsing pyramid pyramid-debugtoolbar pyramid-mako pyramid-beaker pysqlite python-dateutil python-ldap python-memcached python-pam recaptcha-client repoze.lru requests simplejson waitress zope.cachedescriptors dogpile.cache dogpile.core psutil py-bcrypt];
+    propagatedBuildInputs = with self; [Babel Beaker FormEncode Mako Markdown MarkupSafe MySQL-python Paste PasteDeploy PasteScript Pygments Pylons Pyro4 Routes SQLAlchemy Tempita URLObject WebError WebHelpers WebHelpers2 WebOb WebTest Whoosh alembic amqplib anyjson appenlight-client authomatic backport-ipaddress celery channelstream colander decorator deform docutils gevent gunicorn infrae.cache ipython iso8601 kombu msgpack-python packaging psycopg2 py-gfm pycrypto pycurl pyparsing pyramid pyramid-debugtoolbar pyramid-mako pyramid-beaker pysqlite python-dateutil python-ldap python-memcached python-pam recaptcha-client repoze.lru requests simplejson subprocess32 waitress zope.cachedescriptors dogpile.cache dogpile.core psutil py-bcrypt];
     src = ./.;
     meta = {
       license = [ { fullName = "AGPLv3, and Commercial License"; } ];

setup.py

@@ -101,6 +101,7 b' requirements = ['
     'repoze.lru',
     'requests',
     'simplejson',
+    'subprocess32',
     'waitress',
     'zope.cachedescriptors',
     'dogpile.cache',