Change virtualenv group to virtualenv

This allows more granular permissions. Any user can be added to the
virtualenv group that needs access without having permission to
anything else. This was motivated by needing a `celery` user to have
access to the virtualenv.

fusionbox/fabric/django/new.py

@@ -161,7 +161,7 @@ def upload_source(gitref, directory):
         # better. Arguably this is less surprising anyway.
         extra_opts_list = ['--copy-dest={}'.format(d) for d in get_src_dir_list()]
         # Remove global permissions, set group to www-data
-        extra_opts_list += ['-g', '--chown=:www-data', '--chmod=o-rwx']
+        extra_opts_list += ['-g', '--chown=:virtualenv', '--chmod=o-rwx']
 
         rsync_project(
             local_dir=local_dir,