Arrange the test logic so that it "binds" to an interface that is up/running

In fact on macosx without the patch I have:
+++
Tests in error: 
  testBasicOperation(org.jboss.modcluster.advertise.AdvertiseListenerImplTestCase): Can't assign requested address
  testMulticastSocketNoCrossTalk(org.jboss.modcluster.advertise.MulticastSocketFactoryImplTestCase): Can't assign requested address
+++
/sbin/ifconfig shows:
macosx:mod_cluster jfclere$ /sbin/ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
	inet6 ::1 prefixlen 128 
	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
	inet 127.0.0.1 netmask 0xff000000 
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 2030
	lladdr 00:19:e3:ff:fe:2e:97:00 
	media: autoselect <full-duplex>
	status: inactive
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ether 00:19:e3:06:ce:3f 
	media: autoselect (<unknown type>)
	status: inactive
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ether 00:17:f2:cc:ea:34 
	inet6 fe80::217:f2ff:fecc:ea34%en0 prefixlen 64 scopeid 0x6 
	inet 10.33.144.4 netmask 0xffffff00 broadcast 10.33.144.255
	media: autoselect (10baseT/UTP <half-duplex>)
	status: active
vboxnet0: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ether 0a:00:27:00:00:00 
en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
	ether 00:1c:42:00:00:08 
	inet6 fe80::21c:42ff:fe00:8%en2 prefixlen 64 scopeid 0x8 
	inet 10.211.55.2 netmask 0xffffff00 broadcast 10.211.55.255
	media: autoselect
	status: active
en3: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
	ether 00:1c:42:00:00:09 
	inet6 fe80::21c:42ff:fe00:9%en3 prefixlen 64 scopeid 0x9 
	inet 10.37.129.2 netmask 0xffffff00 broadcast 10.37.129.255
	media: autoselect
	status: active
+++
without the patch it seems it uses a wrong interface