404 response for a HEAD on an object returns a body, violating HTTP/1.1 spec

[Tomoe Sugihara]

Release: Liberty
Platform: RDO on CentOS7

HEAD request for an non-existent object returns 404 (correct) with a body(incorrect), which violates HTTP/1.1 standard:
https://tools.ietf.org/html/rfc7231#section-4.3.2

This leads to a weird behavior in aws-sdk-ruby (1.60.2) where it tries to read the next response after HEAD and parse the status code, but it ends up reading the body that was incorrectly returned by the previous 404 response.

This is causing a problem for bosh director to access swift as a S3 compatible storage.

ref:
https://<email address hidden>/message/WZDC277UP67IHQKSRQXGSDKSMUOSN34L/