Fix #20930: automatic closing is not triggered on very first push.
requested to merge seb4stien/gitlab-ce:20930-very-first-commit-to-default-branch-didn-t-close-referenced-issue into master
What does this MR do?
Notice users about the fact that automatic issue closing is disabled on very first push for performance reasons (see #20930 (moved)).
Fix #20930 (moved)