Use xvideo in QGstreamerPlayerService

XVideo performance is much better than overlay on N9xx, and is used
for camerabin already.

Signed-off-by: John Brooks <john.brooks@dereferenced.net>
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 <matthew.vogt@jollamobile.com>
fix for MER#625

Don't unref if operation did not succeed

Signed-off-by: Vesa-Matti Hartikainen <vesa-matti.hartikainen@jollamobile.com>
Fix query syntax for PhotoAlbum children.

The nie:isLogicalPartOf(?x) syntax won't match against an id, so this
query would never return anything.  Instead return the contents
of the list rather than relying on a connection that may never
be established.

The same query will also return the contents of a Playlist, support
for which was mysteriously absent.

Change-Id: Id448e06f8d183e064c8966b22d44414057a45f8a
Reviewed-by: Christopher Adams <chris.adams@jollamobile.com>