fixed OAuth1 authorization header (bug introduced by commit c6e2d74eca2b8bc6f9d9aea183655886e49b5216)

The commit c6e2d74 breaks the authorization in cases when `$bodyParams` is not empty. In such cases `$parameters` will get `oauth_verifier` key from `$bodyParams` (which is necessary only to make a signature) and puts it into the final authorization header, so authorization fails because of the wrong signature (example, try `FitBit` authorization).

These changes made better naming and fixed the authorization headers in such cases.