Fix BC_UCLO insertion for returns.

Contributed by XmiliaH.

src/lj_parse.c

@@ -1570,7 +1570,7 @@ static void fs_fixup_ret(FuncState *fs)
 	/* Replace with UCLO plus branch. */
 	fs->bcbase[pc].ins = BCINS_AD(BC_UCLO, 0, offset);
 	break;
-      case BC_UCLO:
+      case BC_FNEW:
 	return;  /* We're done. */
       default:
 	break;