qemu: Fix qemuProcessAutoDestroy

qemu: Fix qemuProcessAutoDestroy

Upon entry from virCloseCallbacksRun, the @dom will have a
Ref and Lock from virDomainObjListFindByUUIDRef, so there's
no need to take an extra reference nor should the code call
virDomainObjEndAPI when done since that both Unref's and
Unlock's the @dom which means the callers call to EndAPI
would be unlocking an unlocked object. At least the Ref
saved the code from referencing something already freed.

Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>