[sv-ac] Proposal for change in disable iff

Hi,
 
I have attached the proposal for the change in the return type of
disable iff condition. Few things to consider are:
  - Should pass action execute when a property gets disabled (disabled
success) ?
  - Should we consider name 'pre-emptive' success as that term is
already used for disable condition ?
 
I am goig to put it on Mantis also.
 
Thanks.
Manisha