Refactor cluster-deregister workflow to mimic cluster-create and catch exceptions in secret creation

Change-Id: I83ab2ebf032df665aa0935dbab36e7234188c984
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/osm_lcm/odu_workflows.py b/osm_lcm/odu_workflows.py
index dac29d2..7e3f163 100644
--- a/osm_lcm/odu_workflows.py
+++ b/osm_lcm/odu_workflows.py
@@ -61,6 +61,7 @@
             },
             "deregister_cluster": {
                 "workflow_function": self.deregister_cluster,
+                "clean_function": self.clean_items_cluster_deregister,
             },
             "create_profile": {
                 "workflow_function": self.create_profile,
@@ -139,6 +140,7 @@
         clean_items_cluster_create,
         clean_items_cluster_update,
         clean_items_cluster_register,
+        clean_items_cluster_deregister,
         get_cluster_credentials,
     )
     from osm_lcm.odu_libs.ksu import (