Make sure issue_closing_pattern includes `%{issue_ref}` instead of `#\d+`when CE is merged into EE.
Required for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1933.
cc @vsizov
Edited by Serena Fang
Required for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1933.
cc @vsizov