vdagentd-xorg-conf: Add Option "NumHeads" "1" to generated xorg.conf
vdagentd-xorg-conf: Add Option "NumHeads" "1" to generated xorg.conf

So that we don't get multiple heads per device on revision 4 qxl devices
in Xinerama setups.

Signed-off-by: Hans de Goede <9fa1be1a5b5729e4c6b404f34c9ce49ff4882fd8@redhat.com>

elmarco/vdagent-gtk,elmarco/vdagent-gtk,elmarco/vdagent-gtk