Make qtbase compile with QT_NO_XMLSTREAMREADER

D-Bus depends on QXmlStreamReader instead of QDom

Change-Id: Ic435970af21ac6e45c4100359ff54bd5793ccce2
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>