Attempt to resolve pool issues on CentOS and REHL

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-cpp/branches/pools-revamp@706034 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/decaf/util/concurrent/Mutex.cpp b/src/main/decaf/util/concurrent/Mutex.cpp
index 2d028b3..47a5097 100644
--- a/src/main/decaf/util/concurrent/Mutex.cpp
+++ b/src/main/decaf/util/concurrent/Mutex.cpp
@@ -36,10 +36,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 Mutex::~Mutex() {
 
-    // Unlock the mutex.
+    // Unlock the mutex, the destruction of the AprPool will take care
+    // of cleaning up the apr_thread_mutex_t allocated in the ctor.
     unlock();
-
-    apr_thread_mutex_destroy( mutex );
 }
 
 ////////////////////////////////////////////////////////////////////////////////