Fixed init crash with autotuning mode (SCAN-420)

src/AIManager.cpp

@@ -227,6 +227,9 @@ void AIManager::periodic_job_i ()
 void AIManager::quitTask ()
     throw (Tango::DevFailed)
 {
+  // Disable periodic messages
+  this->enable_periodic_msg (false);
+
   try
   {
     if (this->m_currentAcquisition)