MT#62253 AmSession: no dlg based loging when dlg gone

If the dlg object is freed, then don't try to log
things based on the call-id value taken from it.

Just do slightly before.

Change-Id: I09e865ca77d64c6c398cf8dc35c189e076fdb26d

core/AmSession.cpp

@@ -100,9 +100,9 @@ AmSession::~AmSession()
       delete *evh;
   }
 
-  delete dlg;
-
   ILOG_DLG(L_DBG, "AmSession destructor finished\n");
+
+  delete dlg;
 }
 
 AmSipDialog* AmSession::createSipDialog()