UDP: see whether new MulticastSocket(mcast_addr, port) works on Solaris

In UDP, we check whether running under Linux. If so, we bind the MulticastSocket to the mcast_addr, else we don't.

If this works under Solaris, we could also bind the MulticastSocket the same way.

[Brian]
dev12 runs Solaris 9 and dev13 runs Solaris 10.

http://docs.jboss.org/process-guide/en/html/qalab.html#d0e5666 is probably somewhat out of date but at least it's right that these are solaris boxes.