Threads initiating SAs can get stuck on the semaphore in
wait_for_listener() during shutdown if the corresponding job is never
executed. A particular case when this can happen is if more initiations
are triggered than worker threads are available. This causes a (known)
deadlock as no workers are free anymore to process jobs (for inbound
messages or timeouts etc.), including the one to initiate an SA.
This change at least allows a proper shutdown.
Tobias Brunner
f8e5e38b12