[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
I'll let someone else make the final call here, but I don't like throwing NPE's. I think an `assert` should be sufficient here. Or just throw an `IllegalArgumentException`.