[gnome-shell/gnome-3-38] ci: Use correct variable name

[Florian Müllner <fmuellner src gnome org>]

commit 5bdcd8236df1d6be5d5273997d0c3d591e55e524
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Dec 11 15:59:11 2020 +0100

    ci: Use correct variable name
    
    Whoops, the last changes accidentally changed the CI_COMMIT_REF_NAME
    variable to something that's not actually defined.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1531>
    (cherry picked from commit ad9c2dd817aab3c8c69d7805ff9162000150d38e)

 .gitlab-ci/checkout-mutter.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci/checkout-mutter.sh b/.gitlab-ci/checkout-mutter.sh
index 999f090616..82096af381 100755
--- a/.gitlab-ci/checkout-mutter.sh
+++ b/.gitlab-ci/checkout-mutter.sh
@@ -41,8 +41,8 @@ if [ "$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" ]; then
 fi
 
 if [ -z "$mutter_target" ]; then
-  echo -n Looking for $CI_COMMIT_REF on remote ...
-  if fetch origin $CI_COMMIT_REF; then
+  echo -n Looking for $CI_COMMIT_REF_NAME on remote ...
+  if fetch origin $CI_COMMIT_REF_NAME; then
     echo \ found
     mutter_target=FETCH_HEAD
   else