def delete(uri)
      headers = { 'Content-Type' => 'application/json' }
      res = Excon.delete(@base_url + uri.to_s,
                         headers: headers,
                         user: username,
                         password: password,
                         ssl_verify_peer: false)
      api_response res
    end
def delete(uri)
      headers = { 'Content-Type' => 'application/json' }
      res = Excon.delete(@base_url + uri.to_s,
                         headers: headers,
                         user: username,
                         password: password,
                         ssl_verify_peer: false)
      api_response res
    end
http request via delete
 @param [string] uri
 @return [Object] ruby representation of the json response
                  if the reponse body  does not parse, raises
                  a SFRest::InvalidResponse