[tracker-miners/tracker-miners-2.3] Fix obvious CI regression that I just introduced.

[Sam Thursfield <sthursfield src gnome org>]

commit 3f1e4d3a409c5cf3b0388bd8a795f4f79a4f7b2c
Author: Sam Thursfield <sam afuera me uk>
Date:   Sat Apr 25 13:35:54 2020 +0200

    Fix obvious CI regression that I just introduced.

 .gitlab-ci/checkout-tracker.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci/checkout-tracker.sh b/.gitlab-ci/checkout-tracker.sh
index 6f31b69c7..4954cbec0 100755
--- a/.gitlab-ci/checkout-tracker.sh
+++ b/.gitlab-ci/checkout-tracker.sh
@@ -29,7 +29,7 @@ fi
 
 if [ -z "$tracker_target" ]; then
   tracker_target=$(git branch -r -l origin/$CI_COMMIT_REF_NAME)
-  tracker_target=${tracker_target:-origin/master}
+  tracker_target=${tracker_target:-origin/tracker-2.3}
   echo Using $tracker_target instead
 fi