Pass oldDev to virDomainDefCompatibleDevice on device update

Pass oldDev to virDomainDefCompatibleDevice on device update

When calling virDomainDefCompatibleDevice to check a new device during
device update, we need to pass the original device which is going to be
updated in addition to the new device. Otherwise, the function can
report false conflicts.

The new argument is currently ignored by virDomainDefCompatibleDevice,
but this will change in the following patch.

https://bugzilla.redhat.com/show_bug.cgi?id=1546971

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>