Fix: crmd: abort transition whenever we lose quorum

If a node drops us below quorum because it was unexpectedly lost, the peer
update callback will abort the transition. If it was shut down cleanly while
running resources, the CIB recovery results will abort the transition. However,
if it was shut down cleanly while not running any resources (e.g. in standby
mode), previously we would not trigger a new transition, and the remaining
nodes would not stop their resources until the next recheck interval.