Keep looping if address is null

This made embark-framework work for me. (More often than not.)

Author: linagee

lib/deploy.js

@@ -71,7 +71,7 @@ Deploy.prototype.deploy_contracts = function(env) {
 
       console.log('trying to obtain ' + className + ' address...');
       var receipt = null;
-      while ((receipt = web3.eth.getTransactionReceipt(transactionHash)) === null) {
+      while ((receipt = web3.eth.getTransactionReceipt(transactionHash)) === null || receipt.contractAddress === null) {
           sleep.sleep(1);
       }
       var contractAddress = receipt.contractAddress;