Allow remotePolling on single (qualified) branch with multiple repositories

[FIXED [JENKINS-25414](https://issues.jenkins-ci.org/browse/JENKINS-25414)]

cherry-picked 0c250cd1c53e351f119b819c879290ce111cd5ef for master branch.
See [this pull request](https://github.com/jenkinsci/git-plugin/pull/267) for 2.2.x branch