ReverseLookup: Don't return OpenCNAM errors as caller IDs

Skip the API entirely for non-US numbers, and ignore any non-200
bodies to avoid names of the "Limit Exceeded" variety

PS2: Use constant from HttpStatus and don't check for null on normalizedNumber
Change-Id: I1ea107ba828e6dba44fa0828ad5fedecb8faf4de
(cherry picked from commit 50cc4c8615d99e92a481981289ff9a7ec83b4c04)