Merge branch 'fix-uncheckable-label-for-force_remove_source_branch' into 'master'

Clicking "force remove source branch" label now toggles the checkbox again

We remove the ID from the hidden tag for `merge_request[force_remove_source_branch]`
in order to fix the checkbox toggling when the associated label is clicked.

The issue was introduced by !7267 and discovered in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7267#note_18028311.

See merge request !7356

app/views/shared/issuable/_form.html.haml

@@ -129,7 +129,7 @@
       .col-sm-10.col-sm-offset-2
         .checkbox
           = label_tag 'merge_request[force_remove_source_branch]' do
-            = hidden_field_tag 'merge_request[force_remove_source_branch]', '0'
+            = hidden_field_tag 'merge_request[force_remove_source_branch]', '0', id: nil
             = check_box_tag 'merge_request[force_remove_source_branch]', '1', @merge_request.force_remove_source_branch?
             Remove source branch when merge request is accepted.
 

changelogs/unreleased/fix-uncheckable-label-for-force_remove_source_branch.yml

+---
+title: Clicking "force remove source branch" label now toggles the checkbox again
+merge_request: 
+author: