Cleaning up versionUpdate branches

[bartoszmajsak]

Apparently, fabric8-cd bot does not cleanup after automerge, which results with tons of stale branches such as versionUpdate1f13c367-fffe-426d-915f-658c2ff30ae0. When the PR is automerged the branch should be deleted if coming from the same repo.

[maxandersen]

would make sense the bot itself open'ed PR's from its "own" branch and if on github do it with "let others edit" flag set rather in the "master" repo.