vl.c: Fix OpenBSD compilation issue due to namespace collisions

Machine rewriting added MACHINE() macro which is
already in use by other OpenBSD library.
Since qemu/sockets.h exposes the OpenBSD namespace,
the minimalistic approach is to add it as the first QEMU include.

Reported-by: Brad Smith <brad@comstyle.com>
Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/vl.c b/vl.c
index 0e82f06..e2e2ac7 100644
--- a/vl.c
+++ b/vl.c
@@ -58,6 +58,7 @@
 
 #include <glib.h>
 
+#include "qemu/sockets.h"
 #include "hw/hw.h"
 #include "hw/boards.h"
 #include "hw/usb.h"
@@ -103,7 +104,6 @@
 
 #include "disas/disas.h"
 
-#include "qemu/sockets.h"
 
 #include "slirp/libslirp.h"