Summary:
Ref T4189. This adds SVN support, which was a little more messy than I though. Principally, we can not use `PHABRICATOR_USER` for Subversion, because it strips away the entire environment for "security reasons".
Instead, use `--tunnel-user` plus `svnlook author` to figure out the author.
Also fix "ssh://" clone URIs, which needs to be "svn+ssh://".
Test Plan:
- Made SVN commits through the hook.
- Made Git commits, too, to make sure I didn't break anything.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T4189
Differential Revision: https://secure.phabricator.com/D7683