Nickserver returns 404 for existing key

--- ~ » curl -k -i --silent --max-time 10 -X GET -d address=foo@example.org https://unstable.bitmask.net:6425
HTTP/1.1 404 Not Found
Date: Tue, 06 Dec 2016 14:52:47 GMT
Server: Apache
Content-Length: 14
X-Frame-Options: DENY

404 Not Found

For foo@example.org there are several keys on the keyservers: https://pgp.mit.edu/pks/lookup?search=foo%40example.org&op=index

Most of them are bogus keys with attempted js expoits in them, but nonetheless, 404 is not the appropriate answer.

(from redmine: created on 2016-12-06, relates #8648 (closed))