Hack around a react warning

when login completes, we replace the whole state, which means we unset
collapse_lhs, which then leads to complaints from the RoomList.

I think the 'default view' for MatrixChat ought to be factored out to another
component, which could manage collapse_lhs properly; but for now, hack around
it.

src/components/views/rooms/RoomList.js

@@ -33,7 +33,7 @@ module.exports = React.createClass({
 
     propTypes: {
         ConferenceHandler: React.PropTypes.any,
-        collapsed: React.PropTypes.bool,
+        collapsed: React.PropTypes.bool.isRequired,
         currentRoom: React.PropTypes.string,
         searchFilter: React.PropTypes.string,
     },