Properly construct DefaultMQPushConsumer (#55)

* Properly construct DefaultMQPushConsumer

* Fix bash path in build.sh
diff --git a/build.sh b/build.sh
index 2261238..32ebe9a 100755
--- a/build.sh
+++ b/build.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/bash
+#!/bin/bash
 
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
diff --git a/src/consumer/DefaultMQPushConsumer.cpp b/src/consumer/DefaultMQPushConsumer.cpp
index 159e0ff..2e78ebc 100644
--- a/src/consumer/DefaultMQPushConsumer.cpp
+++ b/src/consumer/DefaultMQPushConsumer.cpp
@@ -202,10 +202,13 @@
     DefaultMQPushConsumer::DefaultMQPushConsumer(const string &groupname)
             : m_consumeFromWhere(CONSUME_FROM_LAST_OFFSET),
               m_pOffsetStore(NULL),
+              m_pRebalance(NULL),
               m_pPullAPIWrapper(NULL),
+              m_consumerService(NULL),
               m_pMessageListener(NULL),
               m_consumeMessageBatchMaxSize(1),
-              m_maxMsgCacheSize(1000) {
+              m_maxMsgCacheSize(1000),
+              m_pullmsgQueue(NULL) {
         //<!set default group name;
         string gname = groupname.empty() ? DEFAULT_CONSUMER_GROUP : groupname;
         setGroupName(gname);