replace boost::thread::hardware_concurrency with std::thread::hardware_concurrency. (#171)

diff --git a/src/common/MQClient.cpp b/src/common/MQClient.cpp
index 42d77a5..b2b9937 100644
--- a/src/common/MQClient.cpp
+++ b/src/common/MQClient.cpp
@@ -41,7 +41,7 @@
   m_instanceName = "DEFAULT";
   m_clientFactory = NULL;
   m_serviceState = CREATE_JUST;
-  m_pullThreadNum = boost::thread::hardware_concurrency();
+  m_pullThreadNum = std::thread::hardware_concurrency();
   m_tcpConnectTimeout = 3000;        // 3s
   m_tcpTransportTryLockTimeout = 3;  // 3s
   m_unitName = "";
diff --git a/src/consumer/DefaultMQPushConsumer.cpp b/src/consumer/DefaultMQPushConsumer.cpp
index caa539e..7e47e15 100644
--- a/src/consumer/DefaultMQPushConsumer.cpp
+++ b/src/consumer/DefaultMQPushConsumer.cpp
@@ -205,8 +205,8 @@
   setMessageModel(CLUSTERING);
 
   m_startTime = UtilAll::currentTimeMillis();
-  m_consumeThreadCount = boost::thread::hardware_concurrency();
-  m_pullMsgThreadPoolNum = boost::thread::hardware_concurrency();
+  m_consumeThreadCount = std::thread::hardware_concurrency();
+  m_pullMsgThreadPoolNum = std::thread::hardware_concurrency();
   m_async_service_thread.reset(new boost::thread(boost::bind(&DefaultMQPushConsumer::boost_asio_work, this)));
 }