fix(@embark/blockchain): fix blockchain plugins' use of async whilst

Author: jrainville

packages/plugins/geth/src/blockchain.js

@@ -337,8 +337,8 @@ class Blockchain {
           if (!newAccountCommand) return next();
           var accountNumber = 0;
           async.whilst(
-            function () {
-              return accountNumber < accountsToCreate;
+            function (cb) {
+              cb(null, accountNumber < accountsToCreate);
             },
             function (callback) {
               accountNumber++;

packages/plugins/parity/src/blockchain.js

@@ -346,8 +346,8 @@ class Blockchain {
         function newAccounts(accountsToCreate, next) {
           var accountNumber = 0;
           async.whilst(
-            function () {
-              return accountNumber < accountsToCreate;
+            function (cb) {
+              cb(null, accountNumber < accountsToCreate);
             },
             function (callback) {
               accountNumber++;