block/qcow2: improve error message in qcow2_inactivate

Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[Maintainer edit -- touched up error message. --js]
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NJohn Snow <jsnow@redhat.com>

block/qcow2.c

@@ -2123,9 +2123,9 @@ static int qcow2_inactivate(BlockDriverState *bs)
     qcow2_store_persistent_dirty_bitmaps(bs, &local_err);
     if (local_err != NULL) {
         result = -EINVAL;
-        error_report_err(local_err);
-        error_report("Persistent bitmaps are lost for node '%s'",
-                     bdrv_get_device_or_node_name(bs));
+        error_reportf_err(local_err, "Lost persistent bitmaps during "
+                          "inactivation of node '%s': ",
+                          bdrv_get_device_or_node_name(bs));
     }
 
     ret = qcow2_cache_flush(bs, s->l2_table_cache);