2344: hack get_subtitle_version to exclude sources

Check the comment in the code for more information.
Pinning python-memcached to the previous version (through a specific github commit) cause the latest pypy package is broken, and the maintainers *delete* the old packages.
Fixed lingering line on requirements.txt
Merge branch 'i-2344' into staging
Merge branch 'staging' into i-2341