Fix regression in UpdateParametersAction

Regression From https://review.opendev.org/#/c/599188/

Change-Id: Ic7274b382bb60dea467bf4d116f80472bfd04e0c
Closes-Bug: #1834086

tripleo_common/actions/parameters.py

@@ -212,7 +212,7 @@ class UpdateParametersAction(base.TripleOAction):
             # There has been an error validating we must reprocess the
             # templates with the saved working env
             plan_utils.put_env(swift, saved_env)
-            self._process_custom_roles(context)
+            process_templates_action._process_custom_roles(context)
 
             err_msg = ("Error validating environment for plan %s: %s" % (
                 self.container, err))