Fix return values in clean_items_cluster_register to progress on registration workflow

Change-Id: Ibf6e5c5a2fab91abb3d38f1e19d02fdba43efa90
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/osm_lcm/odu_libs/cluster_mgmt.py b/osm_lcm/odu_libs/cluster_mgmt.py
index 98f308a..c088d10 100644
--- a/osm_lcm/odu_libs/cluster_mgmt.py
+++ b/osm_lcm/odu_libs/cluster_mgmt.py
@@ -430,6 +430,7 @@
 
     try:
         await self.clean_items(items)
+        return True, "OK"
     except Exception as e:
         return False, f"Error while cleaning items: {e}"