message: Fix URL previews
  and also things like the unsent message error and encryption
  warning.
  Stuff that we need to do at room view mount time had got moved into
  a clause of the if statement in onHaveRoom and so wasn't being
  executed.
  Fixes
diff: @@ -230,6 +230,10 @@ module.exports = React.createClass({
  if (room) {
  this._updateAutoComplete(room);
  this.tabComplete.loadEntries(room);
  + this.setState({
  + unsentMessageError: this._getUnsentMessageError(room),
  + });
  + this._onRoomLoaded(room);
  }
  if (!this.state.joining && this.state.roomId) {
  if (this.props.autoJoin) {
  @@ -262,10 +266,6 @@ module.exports = React.createClass({
  } else if (room) {
  // Stop peeking because we have joined this room previously
  MatrixClientPeg.get().stopPeeking();
  - this.setState({
  - unsentMessageError: this._getUnsentMessageError(room),
  - });
  - this._onRoomLoaded(room);
  }
  },
  