oauth with instagram broken

What steps will reproduce the problem?

try oauth with instagram api, after user accepts instagram app,
exchange user provided code for instagram access_token with Transport.Exchange()

What is the expected output? What do you see instead?

Expected: getting the access token from instagram
Getting Error: 
code: 400,
error_type: "OAuthException",
error_message: "You must provide a client_secret"

What version of the product are you using? On what operating system?

current version, fresh go get code.google.com/p/goauth2/oauth

Please provide any additional information below.

An issue was fixed 6 days ago, putting the client_id for calls to google as 
form parameter. This works for instagram too!

Fix for google: https://codereview.appspot.com/129150043

I tried adding Instagram as exception in oauth.go -> providerAuthHeaderWorks():

    if strings.HasPrefix(tokenURL, "https://api.instagram.com/oauth") {
        return false
    }

which works.

Original issue reported on code.google.com by david.kn...@freiheit.com on 20 Aug 2014 at 10:08

badu / goauth2

oauth with instagram broken #39