version.py: remote repo fix for http remotes

We check out theme repos using a git HTTP url (git://) instead of git ssh url (git@).  To make the version script work we need to generalize the regexp used to parse out the remotes.  This was causing errors.

To test I just tried this out in a REPL, see below:

    In [15]: for line in lines:
        print line
       ....:
    origingit@github.com:edx/edx-platform.git (fetch)
    origingit@github.com:edx/edx-platformrm.git (push)
    origingit://github.com/Stanford-Online/edx-theme.git (fetchtch)
    origingit://github.com/Stanford-Online/edx-theme.git (push)

    In [In16]: for line in lines:
       ....:     if ' (fetch)' in line:
       ....:         repo_url = re.search(
       ....:         '(git@|git://)(.*) \(fetch\)', line).group(2).replace(
       ....:         ':', '/')
       ....:         print repo_url
       ....:
    github.com/edx/edx-platform.git
    github.com/Stanford-Online/edx-theme.git

Please review @e0d or @jarv