[gnome-shell] ci: Use custom image for commit log check

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit f81ac498fbb9a12cfefe52ec363a09e6d0cd48c8
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Apr 3 13:28:32 2019 +0200

    ci: Use custom image for commit log check
    
    We can speed up the check a little bit by using an image that
    already contains git, so do that.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/480

 .gitlab-ci.yml | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ea91cec00..1c662ce3a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,10 +15,8 @@ variables:
         - merge_requests
 
 check_commit_log:
-    image: registry.fedoraproject.org/fedora:latest
+    image: registry.gitlab.gnome.org/gnome/mutter/master:v1
     stage: review
-    before_script:
-        - dnf install -y git
     script:
         - ./.gitlab-ci/check-commit-log.sh
     only: