[mutter] ci: Fix checkout out gnome-shell on stable branches

[Florian Müllner <fmuellner src gnome org>]

commit 91729014583dc81ed4895bc7e5660c3f007815f3
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Nov 7 00:05:12 2019 +0100

    ci: Fix checkout out gnome-shell on stable branches
    
    For stable branches, we currently only check out the correct shell
    branch for merge requests. For the regular pipeline, our code to
    determine the current mutter branch fails because CI runs on a
    temporary "pipeline/12345" branch that doesn't exist for gnome-shell.
    
    Switching to the correct gitlab environment variable fixes that.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/811

 .gitlab-ci/checkout-gnome-shell.sh | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/.gitlab-ci/checkout-gnome-shell.sh b/.gitlab-ci/checkout-gnome-shell.sh
index 64c1af953..bcfbfe7a7 100755
--- a/.gitlab-ci/checkout-gnome-shell.sh
+++ b/.gitlab-ci/checkout-gnome-shell.sh
@@ -1,6 +1,5 @@
 #!/usr/bin/bash
 
-mutter_branch=$(git describe --contains --all HEAD)
 gnome_shell_target=
 
 git clone https://gitlab.gnome.org/GNOME/gnome-shell.git
@@ -26,8 +25,7 @@ if [ "$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" ]; then
 fi
 
 if [ -z "$gnome_shell_target" ]; then
-  gnome_shell_target=$(git branch -r -l origin/$mutter_branch)
-  gnome_shell_target=${gnome_shell_target:-$(git branch -r -l ${mutter_branch#remotes/})}
+  gnome_shell_target=$(git branch -r -l origin/$CI_COMMIT_REF_NAME)
   gnome_shell_target=${gnome_shell_target:-origin/master}
   echo Using $gnome_shell_target instead
 fi