When upgrading from Gerrit 2.13 to 3.2 we stopped relying on a local
fork of its source and have been building from (more recently
completely unmolested) upstream source. This fork was the only place
we were relying on jeepyb's track-upstream feature, so we can stop
looking for it in our checks and normalization as well.
Remove the check_gerrit_projects_changed scripts as well, as they
only existed to run things where track-upstream was enabled.
Change-Id: I597c1a577c53e2db61413d9ec531378667691d2a
ef03e7fa36