Adding new cluster update function

Change-Id: I5733e7daf6189339836485f3d9d841f2647cad88
Signed-off-by: yshah <shahithya.y@tataelxsi.co.in>
diff --git a/osm_lcm/lcm.py b/osm_lcm/lcm.py
index 89d877b..fe93778 100644
--- a/osm_lcm/lcm.py
+++ b/osm_lcm/lcm.py
@@ -863,7 +863,7 @@
                     "cluster", cluster_id, cluster_id, "cluster_get_credentials", task
                 )
                 return
-            elif command == "upgrade" or command == "scale":
+            elif command == "upgrade" or command == "scale" or command == "update":
                 # db_vim = self.db.get_one("vim_accounts", {"_id": db_cluster["vim_account"]})
                 db_vim = self.db.get_one(
                     "vim_accounts", {"name": db_cluster["vim_account"]}