The stop event should already be signaled by the time we get to that
point since we wait until the child processes terminate in the server
process and the stop event is signaled in the context of one of the
child processes.

Don't call RpcMgmtWaitServerListening if the call to
WaitForSingleObject failed since it is likely that s_stop() hasn't
been called and therefore the call to RpcMgmtWaitServerListening won't
ever return.