qemu: Do not report completed stats until the job finishes

We would happily report and free statistics of a completed migration
even before it actually completed (on the source host while migration is
in the Finish phase).
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_driver.c

@@ -13016,7 +13016,9 @@ qemuDomainGetJobStatsInternal(virQEMUDriverPtr driver,
         goto cleanup;
     }
 
-    if (completed)
+    if (completed && priv->job.current)
+        info = NULL;
+    else if (completed)
         info = priv->job.completed;
     else
         info = priv->job.current;