Handle the case where a resource pool has no ancestors 
Handle the case where a resource pool has no ancestors 

fixes #1213(transferred from ManageIQ/manageiq@b43384107e6ff4c71f8fa2a756fbe0594943fb3c)

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