this is a quick fix just to prevent the error - undefined method `new_vm' for nil:NilClass

to check if the selected compute resource id is also in the new list, I still need to:
1) set compute_resource_id to "", 
2) run update_form to get get scoped list, 
3) compared the option list values to the original
4) re-assign the original compute_resource_id to the original value if in list.  If not, keep blank.