Make sure pid file lock is properly inherited
Make sure pid file lock is properly inherited

Make sure the pid file descriptor is inherited, so that pid file lock is
inherited.

electrum/airlift,dain/airlift,airlift/airlift,airlift/airlift,electrum/airlift,electrum/airlift,airlift/airlift,dain/airlift,dain/airlift,airlift/airlift,dain/airlift,electrum/airlift