Bring QtDBus meta-object generator in sync with moc

Bring QtDBus meta-object generator in sync with moc

QtDBus's meta-object generator should generate objects of the same
version as moc; in the future, when the moc version is bumped,
QtDBus's meta-object generator has to be adapted at the same time.

Since QMetaObjectPrivate and related flags reside in qmetaobject_p.h,
QtDBus can just include the header instead of duplicating code.
qmetaobject_p.h also defines the meta-object revision QtDBus should
be targeting.

QtDBus was generating version 3 meta-objects. This patch makes it
generate version 6 (the current version). Since a new field was
added to QMetaObjectPrivate in revision 4 (signalCount), the
generator had to be adapted. In particular, the signal definitions
need to come before other methods (as they do with moc), since
there are functions in QObject that rely on that (e.g.
computeOffsets()).

Change-Id: I37f102d8c1be372ef6cfaf013baa87f9abb0fd5e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>