Bumps Gitlab Shell version to 6.0.3
Needed in order for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16547/diffs to work completely because of gitlab-shell!186 (merged)
Needed in order for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16547/diffs to work completely because of gitlab-shell!186 (merged)