Reduce message passing through rexi_server

There's no need to have rexi_server handle every process exit. There's
already an exception handler and workers can report on their own exit
reasons selectively. This also changes job tracking into a concurrent
ets update so if an RPC worker doesn't die in rexi code then rexi_server
will only handle half of the message passing load since we no longer
have to handle process exits.
1 file changed