From RFC2616 (https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2):
> It MUST be possible to combine the multiple header fields into one "field-name: field-value" pair,
> without changing the semantics of the message, by appending each subsequent field-value to the first,
> each separated by a comma.
This was correct before, but this simplifes a bit and shaves off a few bytes from the response.
Signed-off-by: Matt Moyer <moyerm@vmware.com>