Linking directly to the system notes a diff discussion doesn't scroll and expand the discussion

This works as expected: https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2399/diffs#note_126623

This doesn't: https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2399/diffs#note_126644

It works on the discussion page: https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2399#note_126644

/cc @smcgivern @andr3