Fix oauth_callback change error

[qnub]

Got error request() got an unexpected keyword argument 'oauth_callback' when try to call .fetch_request_token(url=self.request_token_url, oauth_callback=self.redirect_uri)

[coveralls]

Coverage remained the same at 86.758% when pulling 08cfa2f on qnub:patch-1 into 476ba75 on requests:master.

[Lukasa]

This change is definitely not right. oauth_callback is not a parameter we accept anywhere. What are you trying to achieve?

[qnub]

@Lukasa sad, because is only way to force twitter to direct user back to URL other than set on apps.twitter.com.

Check «Step 1» here https://dev.twitter.com/web/sign-in/implementing:

The only unique parameter in this request is oauth_callback, which must be a URL-encoded version of the URL you wish your user to be redirected to when they complete step 2.

[Lukasa]

If you want to set a parameter, you should use params= instead. =)

[qnub]

Have you tryed to do that? Seems it's not work.

[Lukasa]

When you say it doesn't work, what specifically do you mean? Additionally, have you tried setting data= instead of params=?