fix off-by-one in interface alias handling. reported by Jose Nazario and Scott Dawson <{jose,sdawson}@arbor.net>
fix off-by-one in interface alias handling. reported by Jose Nazario and Scott Dawson <{jose,sdawson}@arbor.net>

insomniacslk/libdnet,insomniacslk/libdnet,insomniacslk/libdnet