Include ResponseParameters in UploadFile error

This makes UploadFile behave more similarly to MakeRequest when the
response is not ok.

bot.go

@@ -226,7 +226,11 @@ func (bot *BotAPI) UploadFile(endpoint string, params map[string]string, fieldna
 	}
 
 	if !apiResp.Ok {
-		return APIResponse{}, errors.New(apiResp.Description)
+		parameters := ResponseParameters{}
+		if apiResp.Parameters != nil {
+			parameters = *apiResp.Parameters
+		}
+		return apiResp, Error{Code: apiResp.ErrorCode, Message: apiResp.Description, ResponseParameters: parameters}
 	}
 
 	return apiResp, nil