changed the Tango db client side timeout

src/ContinuousAO.cpp

@@ -1447,7 +1447,7 @@ void ContinuousAO::save_waveform(double* waveform, string wfm_channel)
   Tango::DbData db_data;
   db_data.push_back(dbdatum);
   
-  get_db_device()->set_timeout_millis(30000);
+  get_db_device()->get_dbase()->set_timeout_millis(30000);
 
   // put the waveform in the database 
   _DEV_TRY