Update gitlab to 10.7.3.
For list of changes look here: https://about.gitlab.com/2018/04/22/gitlab-10-7-released/
Please note that gitlab-pages is temporarily removed and will be added later if upstream bug is fixed.
To not update to this version if you require gitlab-pages.
The Gemfile.lock is now generated on gitlab startup, so this should help with Gemfile issues.

Reviewed by: swills (mentor)
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D15314