npm registry returns 406 error for tarballs?

[rlidwka]

[sinopia-714 (out) 2013-12-26T13:41:47] http <-- 500, user: undefined, req: 'GET /nodemailer/-/nodemailer-0.5.15.tgz?', error: bad uplink status code: 406
[sinopia-714 (out) 2013-12-26T13:41:47] http --> 406, req: 'GET http://registry.npmjs.org/nodemailer/-/nodemailer-0.5.15.tgz', bytes: 0/134

needs investigation

[rlidwka]

1. sinopia adds wrong accept header
2. npm registry doesn't add vary: accept header

GET /date-utils/-/date-utils-1.2.15.tgz HTTP/1.1
Accept: application/json
User-Agent: Sinopia/0.5.7
host: registry.npmjs.org
Connection: keep-alive

HTTP/1.1 406 Not Acceptable
Etag: 4828df19-7160-c331-e947-a86707c2d667
Last-Modified: Thu, 19 Dec 2013 17:27:02 GMT
Content-Type: application/json
Content-MD5: CJhnV1DxSuXLLG0g+zWelg==
Server: Manta
x-request-id: ceefec40-6e61-11e3-ad31-5ff1673825af
x-response-time: 15
x-server-name: c84b3cab-1c20-4566-a880-0e202b6b63dd
Content-Length: 134
Accept-Ranges: bytes
Date: Thu, 26 Dec 2013 19:13:31 GMT
Via: 1.1 varnish
Age: 0
Connection: keep-alive
X-Served-By: cache-fra1227-FRA
X-Cache: MISS
X-Cache-Hits: 0
X-Timer: S1388085211.344256878,VS0,VE111

{"code":"NotAcceptable","message":"/isaacs/public/npm/date-utils/_attachments/date-utils-1.2.15.tgz accepts application/octet-stream"}