Revert to UNSAFE_componentWillMount where componentDidMount will not work

src/components/structures/RoomDirectory.js

@@ -56,7 +56,8 @@ export default createReactClass({
         };
     },
 
-    componentDidMount: function() {
+    // TODO: [REACT-WARNING] Move this to constructor
+    UNSAFE_componentWillMount: function() {
         this._unmounted = false;
         this.nextBatch = null;
         this.filterTimeout = null;