Revert revision: 053bfe8ad9, this cause some crash.

Use dynamic_cast more is safer.
I think no more crash on db code.

--HG--
branch : trunk

src/shared/Database/SqlDelayThread.cpp

@@ -32,13 +32,14 @@ void SqlDelayThread::run()
     mysql_thread_init();
     #endif
 
+    SqlAsyncTask * s = NULL;
     // Lets wait for next async task no more than 2 secs
     ACE_Time_Value _time(2);
     while (m_running)
     {
         // if the running state gets turned off while sleeping
         // empty the queue before exiting
-        SqlAsyncTask * s = (SqlAsyncTask*)m_sqlQueue.dequeue(/*&_time*/);
+        s = dynamic_cast<SqlAsyncTask*> (m_sqlQueue.dequeue());
         if(s)
         {
             s->call();