[gnome-autoar/wip/lantw/autoar-0.2] tests: Use positive exit status number

[Ting-Wei Lan <lantw src gnome org>]

commit 18bbe79f2023180d7e1cfa0cb2f1998da5f91e12
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Tue Jan 17 04:51:46 2017 +0800

    tests: Use positive exit status number
    
    Parent processes can only obtain the lowest 8 bits with wait* functions
    on Unix-like systems,

 tests/test-extract-unit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/test-extract-unit.c b/tests/test-extract-unit.c
index 23977b3..94a04c2 100644
--- a/tests/test-extract-unit.c
+++ b/tests/test-extract-unit.c
@@ -967,7 +967,7 @@ main (int argc,
   int tests_result;
 
   if (!setup_extract_tests_directory (argv[0])) {
-    return -1;
+    return 255;
   }
 
   g_test_init (&argc, &argv, NULL);