[gnome-shell] ci: Fix checking out mutter for stable branches

[Florian Müllner <fmuellner src gnome org>]

commit 594a07002911a3f8ef4337ec1d034fd37713b28c
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Apr 23 16:36:35 2019 +0000

    ci: Fix checking out mutter for stable branches
    
    Remote branches always start with the remote itself, so just looking
    for "gnome-3-32" etc. won't produce a match.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/509

 .gitlab-ci/checkout-mutter.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci/checkout-mutter.sh b/.gitlab-ci/checkout-mutter.sh
index 6539d80ea..7eb5c2974 100755
--- a/.gitlab-ci/checkout-mutter.sh
+++ b/.gitlab-ci/checkout-mutter.sh
@@ -23,7 +23,7 @@ if [ "$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" ]; then
 fi
 
 if [ -z "$mutter_target" ]; then
-  mutter_target=$(git branch -r -l $shell_branch)
+  mutter_target=$(git branch -r -l origin/$shell_branch)
   mutter_target=${mutter_target:-origin/master}
   echo Using $mutter_target instead
 fi