fixed the code

contracts/test-helpers/PullPaymentMock.sol

@@ -7,9 +7,6 @@ contract PullPaymentMock is PullPayment {
   function PullPaymentMock() payable { }
 
   // test helper function to call asyncSend
-
-  function PullPaymentMock() payable { }
-
   function callSend(address dest, uint amount) {
     asyncSend(dest, amount);
   }