Fix bug in NetHostDB.scan.  Single zeros weren't scanned properly. Included regression test.
Fix bug in NetHostDB.scan.  Single zeros weren't scanned properly.
Included regression test.

polyml/polyml,polyml/polyml,dcjm/polyml,dcjm/polyml,dcjm/polyml,dcjm/polyml,polyml/polyml,polyml/polyml