A quick patch against MrSwitch/node-oauth-shim#1

http://developer.yahoo.com/oauth/guide/oauth-accesstoken.html

Not sure, but for some reason, this 'extra' string (A%3D or A=) comes up in OAUTH-RESPONSE-DATA, and messes up the next steps, mainly the access_token gets cut-off at 'A'

Removing it doesn't seem to cause any problems. Is is either a bug in Yahoo OAuth, or this string is not required.

The documentation actually shows that A%3D is the start of the oauth_response, but doesn't explain why such seemingly URL character %3D is included in token?