Changes

Use gerrit as osmo-ttcn3-hacks.git git remote

Other remotes are mirrors of gerrit one, which means there's some delay
between pushing some ref to the gerrit remote and having them available
in the mirrors.
Hence, it becomes annoying while developing and new stuff to test is
pushed. Let's simply use gerrit since it's the master remote.

Change-Id: Ic87c196f8b91a3a3e6ddde2cca36482ce7070df7