SubmitOnPushIT: Grant push permission when pushing a tag

The intent of I4e580e2f is that this permission is required when
pushing new commits that do not exist on the server. Due to various
bugs in the current implementation of ReceiveCommits, that requirement
is not enforced in this case, but we want to be able to fix those
bugs.

Theoretically, it should be possible to inspect the rest of the
command set in order to determine whether the commits being pushed
here will still be "new" after the rest of the push is processed. But
doing that in a consistent and predictable way is more effort than
it's worth. For the scenario exercised in this specific test, even if
the user cannot be granted push permission, they can use the simple
workaround of pushing once to submit and again to create the tag.

Change-Id: I2b1f2baa825e16049ab6f9c66c9a53be2a1001c1
1 file changed