title: How to change the default target branch for merges in Gitlab
body: <p>we are using Gitlab 8.10.1 with many groups and projects. Many of the projects happen to be forks of other projects.
  Our problem is that whenever somebody opens a merge request for a project the default target branch is NOT the default branch of the project but from one very specific other project. Is there a way to override this setting somehow?
  Just to make it clear, I know how to set the default branch of a project and those settings appear to be correct, however gitlab doesn't seem to use them when creating merge requests.
  This issue is very annoying and has led to weird situations when people didn't pay attention and made merge requests with a completely different "master" as target.</p>