RoomDirectory: use SimpleRoomHeader instead of RoomHeader
RoomDirectory: use SimpleRoomHeader instead of RoomHeader

SimpleRoomHeader and RoomHeader are now separate things
(https://github.com/matrix-org/matrix-react-sdk/pull/252), so update Vector
accordingly.

KentShikama/vector-web,vector-im/vector-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,KentShikama/vector-web,vector-im/vector-web,martindale/vector,vector-im/riot-web,KentShikama/vector-web,KentShikama/vector-web,vector-im/vector-web,martindale/vector,KentShikama/vector-web,vector-im/vector-web,KentShikama/vector-web,vector-im/riot-web,vector-im/vector-web