message: Fixup: dont assume there is a prior edit
diff: @@ -206,7 +206,7 @@ export default class MessageEditor extends React.Component {
  _cancelPreviousPendingEdit() {
  const originalEvent = this.props.editState.getEvent();
  const previousEdit = originalEvent.replacingEvent();
  - if (previousEdit.status === EventStatus.QUEUED || previousEdit.status === EventStatus.NOT_SENT) {
  + if (previousEdit && (previousEdit.status === EventStatus.QUEUED || previousEdit.status === EventStatus.NOT_SENT)) {
  this.context.matrixClient.cancelPendingEvent(previousEdit);
  }
  }
  