pua_dialoginfo: don't free dlginfo structure in dlg loaded callback

- the structure will be destroyed in a later dlg callback, enabled by
  dlg_api.register_dlgcb(), via free_dlginfo_cell()
- based and includes partial patch from GH #492, by Phil Lavin

modules/pua_dialoginfo/pua_dialoginfo.c

@@ -609,7 +609,11 @@ __dialog_loaded(struct dlg_cell *dlg, int type, struct dlg_cb_params *_params)
 	LM_DBG("INVITE dialog loaded: from=%.*s\n", dlg->from_uri.len, dlg->from_uri.s);
 
 	dlginfo=get_dialog_data(dlg, type);
-	if(dlginfo!=NULL) free_dlginfo_cell(dlginfo);
+	if(dlginfo!=NULL) {
+		LM_DBG("dialog info initialized (from=%.*s)\n",
+				dlg->from_uri.len, dlg->from_uri.s);
+		/* free_dlginfo_cell(dlginfo); */
+	}
 }