Handle UnknownHostException

- If the host system's local hostname is not resolvable, a UnknownHostException is thrown in the
   shouldDetermineIfAddressIsLocal test. This caused the test run to stop. This change resolves the
   IP using localhost in the event of an UnknownHostException.
Merge pull request #696 from signed8bit/master

Handle UnknownHostException in SystemUtilTest