IPv4 stack preference removed from run.sh and should be reinstated.

The IPv4 stack preference system property java.net.preferIPv4Stack=true was removed from run.sh during IPv6 modifications to the CP branch. The CP branch is not planned to be IPv6 compatible, so the IPv4 stack preference should
be reinstated.

The error manifests itself in a JGroups warning upon system startup:

14:57:03,375 WARN [UDP] could not bind to /239.11.12.13 (IPv4 address); make sure your mcast_addr is of the same type as the preferred IP stack (IPv4 or IPv6) by checking the value of the system properties java.net.preferIPv4Stack and java.net.preferIPv6Addresses.
Will ignore mcast_addr, but this may lead to cross talking (see http://www.jboss.com/wiki/Edit.jsp?page=CrossTalking for details).
Exception was: java.net.BindException: Cannot assign requested address

Resetting the stack preference causes the JGroups warning to disappear.