alphagov/cdn-acceptance-tests — pull request #18 by dcarley (2014-06-11 08:05:14+00:00)
Title: Don't print "<nil>" when IP cannot be parsed

We only enter this condition when `receivedHeaderIP` is `nil` which results
in the error message saying `with non-IP value ""`.

Instead print the original unparsed value. So that it's clearer why a
non-empty header value couldn't be validated as an IP address.