Revert "Fix printing of semitransparent images to PDF"

The patch was incorrect and caused semi-transparent images
have inversed colors instead of fixing it.

This reverts commit 624740cdcdd4abfb15bbbc8a8aa056c57712499f.

Change-Id: I3f1fa17309fcb53995520843449aae972e0090b8
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Remove direct linkage to dbus and qdbus

It appears that there is no code in the plugin that actually uses dbus.

Change-Id: I654cf0b8f5ecc018f2c6ae8701220f7496915a60
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>