qtest: Include system headers before user headers

It is dangerous to include user headers before system headers since user
macros can affect system headers.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/tests/qom-test.c b/tests/qom-test.c
index 3316a11..b6671fb 100644
--- a/tests/qom-test.c
+++ b/tests/qom-test.c
@@ -6,10 +6,11 @@
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  */
-#include "libqtest.h"
 
 #include <glib.h>
 #include <string.h>
+
+#include "libqtest.h"
 #include "qemu/osdep.h"
 #include "qapi/qmp/types.h"