Handle PREEMPT AND ABORT service action equal to PREEMPT.

With command serialization used in CTL, there are no other commands to abort
when PREEMPT AND ABORT gets to run, so it is practically equal to PREEMPT.

MFC after:	1 week

(cherry picked from commit 99c3fb2ddfe920b5e8fcb76ba755e376e9b24f7c)