if singleWorker crashed, the thread couldn't be joined. This both makes it so that it doesn't crash, as well as reorders the shutdown sequence so that it is less likely to be triggered. Fixes Bitmessage#549
if singleWorker crashed, the thread couldn't be joined. This both makes it so that it doesn't crash, as well as reorders the shutdown sequence so that it is less likely to be triggered. Fixes Bitmessage#549