Fix missing namespace macro warnings when building Qt Addon modules.

Addon modules may not be in the standard Qt namespace and therefore do
not use the QT_{BEGIN,END}_NAMESPACE macros.  Instead module specific
QT_{BEGIN,END}_NAMESPACE_FOO macros are used.  Extend the syncqt test
to allow for this and ensure that the QT_END_NAMESPACE suffix matches
the QT_BEGIN_NAMESPACE suffix.

Change-Id: I33110c01118b0fb4376307db7447f747fc38bb29
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>