MAX_NO_OF_CONNECTIONS + PROTECTED_FDS.
(initialize): Use getrlimit/setrlimit if USING_RLIMIT_NOFILE is
	defined.  Check that getrlimit after setrlimit returns a sane
	value.  Don't use sysconf(_SC_OPEN_MAX), since getrlimit
	provides a better value.  Set fd_ceiling instead of
	MAX_NO_OF_CONNECTIONS.  Make it possible to lower the ceiling
	even when we don't have a working setrlimit.  Removed the
	final sanity checks; the world ain't sane.