forked from remote/oauth2
Per https://developer.gitter.im/docs/authentication#2-gitter-redirects-back-to-your-site ,
both client_id and client_secret are required request parameters.
Change-Id: I64e40be0ab86ec5aea45597b6582e8059d5117cb
GitHub-Last-Rev: d1f5c9ebe6
GitHub-Pull-Request: golang/oauth2#346
Reviewed-on: https://go-review.googlesource.com/c/150557
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>