[glib] gio/tests: Fix build with -Werror=format-security

[Rico Tzschichholz <ricotz src gnome org>]

commit 8911cee350575f7c0b534d97fd10787181c0e542
Author: Rico Tzschichholz <ricotz t-online de>
Date:   Sat Oct 27 12:12:29 2012 +0200

    gio/tests: Fix build with -Werror=format-security

 gio/tests/gdbus-peer-object-manager.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gio/tests/gdbus-peer-object-manager.c b/gio/tests/gdbus-peer-object-manager.c
index 3689b93..89537cc 100644
--- a/gio/tests/gdbus-peer-object-manager.c
+++ b/gio/tests/gdbus-peer-object-manager.c
@@ -221,7 +221,7 @@ setup (Test *test,
   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pair) < 0)
     {
       g_set_error (&error, G_IO_ERROR, g_io_error_from_errno (errno),
-                   g_strerror (errno));
+                   "%s", g_strerror (errno));
       g_assert_no_error (error);
     }