Fix -updateRCUSchemaPassword failed when it has new custom datasource (#876)

* This fixes the case when updating the rcu schema password in the model but at the same time there is a new datasource

Author: jshum2479

core/src/main/python/wlsdeploy/tool/util/rcu_helper.py

@@ -54,6 +54,14 @@ def update_rcu_password(self):
             for ds_name in ds_names:
                 location = deployer_utils.get_jdbc_driver_params_location(ds_name, self.aliases)
                 password_location = LocationContext(location)
+                list_path = self.aliases.get_wlst_list_path(location)
+                if not self.wlst_helper.path_exists(list_path):
+                    # For update case when a new custom data source has not been persisted,
+                    # the driver params location is just a placeholder and will result in error
+                    # if we try to get the attribute list from the location.
+                    # Since we only care about rcu stock data sources from the template for changing
+                    # rcu schema password; we can skip for any new custom data source.
+                    continue
 
                 wlst_path = self.aliases.get_wlst_attributes_path(location)
                 self.wlst_helper.cd(wlst_path)