Improve QSystemDeviceInfo::uniqueDeviceID value
Improve QSystemDeviceInfo::uniqueDeviceID value

For non-specific linux variants, if DBUS is present prefer to return
the exported localMachineId value.  Otherwise fallback to a random but
persistent UUID value, which is more likely to be unique than the result
of gethostid().

Change-Id: I728fd24087caae3ff95693c224887bbcc03e7484
Signed-off-by: Matthew Vogt <a25602bb3d0bdc453c5491edb1c4d02a5d529349@jollamobile.com>

kaltsi/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility