osm.py fix bug in ns-action parameters, missing action_name

Change-Id: I937cc42d65e0a595e27bf7e571de814eefa44f26
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

osmclient/scripts/osm.py

@@ -1073,6 +1073,7 @@ def vcs_list(ctx):
 def ns_action(ctx,
               ns_name,
               vnf_name,
+              action_name,
               params):
     '''executes an action/primitive over a NS instance