[libglnx] tests/xattrs: Fix possible NULL allocation

[Colin Walters <walters src gnome org>]

commit 0c1603debac440978c1d55c46cb11059f8350b35
Author: Colin Walters <walters verbum org>
Date:   Tue Feb 21 09:30:19 2017 -0500

    tests/xattrs: Fix possible NULL allocation
    
    This showed up in the ostree runs with `-fsanitize=undefined` - if we happened
    to get `0` then `g_malloc` would return `NULL`. However, what's interesting is
    it seemed to happen *consistently*. I think what's going on is GCC proved that
    the value *could* be zero, and hence it *could* return NULL, and hence it was
    undefined behavior. Hooray for `-fsanitize=undefined`.

 tests/test-libglnx-xattrs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/test-libglnx-xattrs.c b/tests/test-libglnx-xattrs.c
index 9a39870..21bdbdb 100644
--- a/tests/test-libglnx-xattrs.c
+++ b/tests/test-libglnx-xattrs.c
@@ -42,7 +42,7 @@ static gboolean
 set_random_xattr_value (int fd, const char *name, GError **error)
 {
   const guint8 randxattrbyte = g_random_int_range (0, 256);
-  const guint32 randxattrvalue_len = g_random_int () % 256; /* Picked to be not too small or large */
+  const guint32 randxattrvalue_len = (g_random_int () % 256) + 1; /* Picked to be not too small or large */
   g_autofree char *randxattrvalue = g_malloc (randxattrvalue_len);
 
   memset (randxattrvalue, randxattrbyte, randxattrvalue_len);