pullrequests: fix "additional changes" js error - make sure all cs tables have a first column to align with (Issue #274) A slight simplification of 16234f629cfb and fixing a JavaScript failure for unauthenticated visits to PRs with pending available changesets. nextFirstincell would be undefined becuase the "Current revision - no change" line didn't have any elements in td, and nextFirstincell.offsetTop would thus fail. Fixed by adding a span around the text. Also clarify that any element is fine - there is no need to check for visibility.