Fix @gtl_url for ems_cluster_controller
Fix @gtl_url for ems_cluster_controller

The @gtl_url needs to be set to action name, not controller name.

This problem would lead to url for GTL icons being rendered incorrectly
(doubled controller name, no action name).
(transferred from ManageIQ/manageiq@35abce138f2521cf2f2f80ee41d147f800a7a53b)

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic