[WFCORE-439] : Wrong format of IPv6 addresses in log entries

Log entries now have URI formatted addresses.

Jira: https://issues.jboss.org/browse/WFCORE-439
BZ: https://bugzilla.redhat.com/show_bug.cgi?id=900564
Actually assert should only ever be used for invariants; in this case an IllegalArgumentException is our convention for null parameters.