Replace D-BUS with correct splling D-Bus in the source code,
Keep the old spelling inside XML DTD declarations for compatibility.
Change-Id: Ifa5d43f9fa1417431c81cf1bce0d897a966409b9
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>