add configuration ifaces for python, xorg and vmcore

Related to #754

Signed-off-by: Jakub Filak <jfilak@redhat.com>
spec: install python, vmcore and xorg conf ifaces

Related to #754

Signed-off-by: Jakub Filak <jfilak@redhat.com>
testsuite: test props of python, vmcore and xorg

Closes to #754

Signed-off-by: Jakub Filak <jfilak@redhat.com>
testsuite: fix dbus-configuration test

OpenGPGCheck is 'True' on Fedora na 'False' on RHEL. A better option for
this test 'ProcessUnpackaged' as it is 'False' on all platforms.

Signed-off-by: Jakub Filak <jfilak@redhat.com>