There were two problems with our gerrit upgrade config diff checking.
The first is that we were comparing using command exit codes after
pipeing diff to tee without setting pipefail. This meant that even if
the diff failed we got an exit code of 0 from tee and everything passed
happily.
Second we were not checking our pre gerrit state diff state. If the old
gerrit version also updated the config on disk we wouldn't get a diff
after upgrading to the new version. I think that is ultimately what
broke for us here because the 3.6 and 3.7 config diffs are empty, but
they differ from what we initially write to disk. As for explaining why
this might happen I can only assume some update to 3.6 made the changes
we saw after we had deployed 3.6.
As a result of checking things more thoroughly we need to update our
config to remove any delta. This removes some extraneous quoting around
gitweb config entries to do that.
Change-Id: I9c7e73d5f64546fb57a21a249b29e2aca9229ac7
91ab316142