message: Handle null from TimelinePanel.getScrollState in RoomView _getScrollState
diff: @@ -1417,7 +1417,8 @@ module.exports = createReactClass({
  const scrollState = messagePanel.getScrollState();
  - if (scrollState.stuckAtBottom) {
  + // getScrollState on TimelinePanel *may* return null, so guard against that
  + if (!scrollState || scrollState.stuckAtBottom) {
  // we don't really expect to be in this state, but it will
  // occasionally happen when no scroll state has been set on the
  // messagePanel (ie, we didn't have an initial event (so it's
  