message: Only insert ELS if it'll be non-empty
diff: @@ -428,7 +428,7 @@ module.exports = createReactClass({
  break;
  }
  - // If RM event is in the summary mark it as such and the RM will be appended after the summary.
  + // If RM event is in the summary, mark it as such and the RM will be appended after the summary.
  if (collapsedMxEv.getId() === this.props.readMarkerEventId) {
  readMarkerInSummary = true;
  }
  @@ -445,10 +445,7 @@ module.exports = createReactClass({
  return this._getTilesForEvent(e, e, e === lastShownEvent);
  }).reduce((a, b) => a.concat(b));
  - if (eventTiles.length === 0) {
  - eventTiles = null;
  - }
  -
  + if (eventTiles.length > 0) {
  ret.push(<EventListSummary
  key="roomcreationsummary"
  events={summarisedEvents}
  @@ -460,6 +457,7 @@ module.exports = createReactClass({
  >
  { eventTiles }
  </EventListSummary>);
  + }
  if (readMarkerInSummary) {
  ret.push(this._getReadMarkerTile(visible));
  