Skip git hooks when squashing

git-annex may add a pre-commit hook on the GitLab server, which will
cause the commit to fail unless git-annex is configured. As there
shouldn't be one on the server normally, ignore all commit hooks.

app/services/merge_requests/squash_service.rb

@@ -42,7 +42,7 @@ module MergeRequests
       )
 
       run_git_command(
-        %W(commit -m #{merge_request.title}),
+        %W(commit --no-verify -m #{merge_request.title}),
         tree_path,
         git_env.merge('GIT_COMMITTER_NAME' => current_user.name,
                       'GIT_COMMITTER_EMAIL' => current_user.email,