dialog: use literal module name for stats group

- prevent conflicts with global exports

src/modules/dialog/dialog.c

@@ -551,7 +551,7 @@ static int mod_init(void)
 #ifdef STATISTICS
 	/* register statistics */
 	if(dlg_enable_stats
-			&& (register_module_stats(exports.name, mod_stats) != 0)) {
+			&& (register_module_stats("dialog", mod_stats) != 0)) {
 		LM_ERR("failed to register statistics\n");
 		return -1;
 	}