Little logging improvement for OAuth2 auth

[Numbered]

In method _exchangeAuthorizationCodeForAccessToken we have just throw new \IPS\Login\Exception( 'generic_error', \IPS\Login\Exception::INTERNAL_ERROR ); if something happened with $response. Now I implement Sony Playstation Network OAuth2 and got non-standard answer at this responce in HTML, not json. So decodeJson() on the response returned NULL and nothing logged in $responce checks.

Will be much better, if this method will check \RuntimeException throwing on the $response and log plain response if it not json.

For example, it might look like that:

    protected function _exchangeAuthorizationCodeForAccessToken($code)
    {
        /* Make the request */
        $data = $this->_authenticatedRequest($this->tokenEndpoint(), array(
            'grant_type'   => 'authorization_code',
            'code'         => $code,
            'redirect_uri' => (string)$this->redirectionEndpoint(),
        ));
        try {
            $response = $data->decodeJson();
        } catch (\RuntimeException $e) {
            \IPS\Log::log(print_r($data, true), 'oauth');
            throw new \IPS\Login\Exception('BAD_JSON', \IPS\Login\Exception::INTERNAL_ERROR);
        }

        // other code not changed...
    }

Thanks.

Something went wrong. Empty error log. <= tags for search if somebody catches the same problem.