Verify remote integration branch is not shadowed locally

[jdigger]

For example, it's possible to have a local branch "origin/master", which can cause all kinds of things to get confused.

Ideally, this should have two parts:

1. Do a check to make sure that the "remote" integration branch name isn't shadowed locally
2. Use this fully-qualified branch name in the scripts (e.g., remotes/origin/master)

[sagarsane]

Yea.. looks like this why some people can also see errors like ambiguous origin/master .