Remove empty line in app/views/projects/merge_requests/index.html.haml

The empty line is the only difference between EE & CE

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6355

app/views/projects/merge_requests/index.html.haml

@@ -27,4 +27,3 @@
         = render 'projects/issuable_by_email', email: new_merge_request_email, issuable_type: 'merge_request'
 - else
   = render 'shared/empty_states/merge_requests', button_path: new_merge_request_path
-