dialog: check xdata length when loading profile from db

src/modules/dialog/dlg_db_handler.c

@@ -457,7 +457,7 @@ int load_dialog_info_from_db(int dlg_hash_size, int fetch_num_rows,
 			dlg_set_toroute(dlg, &toroute_name);
 
 			GET_STR_VALUE(xdata, values, 21, 0, 0);
-			if(xdata.s!=NULL && dlg->state!=DLG_STATE_DELETED)
+			if(xdata.len > 0 && xdata.s!=NULL && dlg->state!=DLG_STATE_DELETED)
 			{
 				srjson_InitDoc(&jdoc, NULL);
 				jdoc.buf = xdata;