Summary: Fixes T4946. Theoretically. Test Plan: iiam also unit tests. also ``` cd /var/repo/X git remote remove origin # simulates origin-missing clone under 1.7.1 cd /path/to/phabricator ./bin/repository pull X ``` and observed no errors Reviewers: epriestley Reviewed By: epriestley Subscribers: Korvin, epriestley Maniphest Tasks: T4946, T5938 Differential Revision: https://secure.phabricator.com/D10855