Only push tags to gerrit

A bare push will attempt to push tags back to upstream repos, which will
not work.

Change-Id: Id516a792a00d1773274fc04bd3fd2c447c9cbd95
Remove run-mirror from jeepyb

run-mirror is now contained in pypi-mirror.

Change-Id: Idce50c39fc043c1ed0cca9ce11da314142e4c0ba
Merge "Remove run-mirror from jeepyb"
Merge "Only push tags to gerrit"