Fix an issue with SVN path construction in the presence of subpath configuration
Summary: D7590 made path construction more consistent, but affected this callsite if a subpath is configured. Currently, we end up with double @@ in the URI.
Test Plan:
- Ran unit tests.
- Ran bin/repostitory discover.
Reviewers: staticshock, btrahan
Reviewed By: btrahan
CC: aran
Differential Revision: https://secure.phabricator.com/D7619