qemu: fix the vm deadlock when deleting a nonexistent iothread

https://bugzilla.redhat.com/show_bug.cgi?id=1218145

Jump to endjob instead of cleanup to fix this deadlock.
Signed-off-by: NLuyao Huang <lhuang@redhat.com>

src/qemu/qemu_driver.c

@@ -6365,7 +6365,7 @@ qemuDomainChgIOThread(virQEMUDriverPtr driver,
                                _("cannot find IOThread '%u' in persistent "
                                  "iothreadids"),
                                iothread_id);
-                goto cleanup;
+                goto endjob;
             }
 
             virDomainIOThreadIDDel(persistentDef, iothread_id);