Don't show commit comment button when user is not signed in.

CHANGELOG

@@ -27,6 +27,7 @@ v 7.10.0 (unreleased)
   - Restrict permissions on backup files
   - Improve oauth accounts UI in profile page
   - Add ability to unlink connected accounts
+  - Don't show commit comment button when user is not signed in.
 v 7.9.0
   - Add HipChat integration documentation (Stan Hu)

app/views/projects/diffs/_text_file.html.haml

@@ -16,7 +16,7 @@
       - else
         %td.old_line
           = link_to raw(type == "new" ? " " : line_old), "##{line_code}", id: line_code
-          - if @comments_allowed
+          - if @comments_allowed && can?(current_user, :write_note, @project)
             = link_to_new_diff_note(line_code)
         %td.new_line{data: {linenumber: line.new_pos}}
           = link_to raw(type == "old" ? " " : line.new_pos) , "##{line_code}", id: line_code