Backport "Pass relevant git environment variables while calling `/allowed`" to 3-6-stable
This backports !112 (merged) to the 3-6-stable
branch. This is required because GitLab 8.13.x needs to support Git 2.11, but is not compatible with the gitlab-shell
changes made in gitlab-shell@v4.0.0
.
/cc @balasankarc