FELIX-3984 - Use default application/realm name of 'other' if none specified

Adding support for defaulting to realmName of 'other' (unless overridden by config) if the LoginModule does not specify one

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1459204 13f79535-47bb-0310-9956-ffa450edef68