Remove the 'pretty' SupportedRoomVersion vector debug operator
Remove the 'pretty' SupportedRoomVersion vector debug operator

This way we conform with Qt standard debug output and do not rely
on a Qt private API.

This also fixes compilation for Qt < 5.7.

Fxrh/libqmatrixclient,QMatrixClient/libqmatrixclient,QMatrixClient/libqmatrixclient