Add a LIMIT 100 to queries in _show_user().
Add a LIMIT 100 to queries in _show_user().

Otherwise, it can fetch up to 1000 items, which somewhat kills the request
handler. This happens when a mapreduce it run on entity Issue, which updates
Issue.modified.

Review URL: http://codereview.appspot.com/4528046

riannucci/rietveldv2,riannucci/rietveldv2