queries to aws-name-server are enforced lowercase only

[timball]

if i have a tag for an instance like "mySuperAwesomeTag" using aws-name-server only lookups for "mysuperawesometag" will return results . whereas in the https://tools.ietf.org/html/rfc4343 sez to make things "case insensitive" . probably easy enough to.lower() everything then do a match .

--timball