vl: export machine_init_done

We have that variable but not exported.  Export that so modules can have
a way to poke on whether machine init has finished.

Meanwhile, set that up even before calling the notifiers, so that
notifiers who may depend on this field will get a correct answer.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180306053320.15401-2-peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/vl.c b/vl.c
index 3ef04ce..26662eb 100644
--- a/vl.c
+++ b/vl.c
@@ -2696,7 +2696,7 @@
     notifier_list_notify(&exit_notifiers, NULL);
 }
 
-static bool machine_init_done;
+bool machine_init_done;
 
 void qemu_add_machine_init_done_notifier(Notifier *notify)
 {
@@ -2713,8 +2713,8 @@
 
 static void qemu_run_machine_init_done_notifiers(void)
 {
-    notifier_list_notify(&machine_init_done_notifiers, NULL);
     machine_init_done = true;
+    notifier_list_notify(&machine_init_done_notifiers, NULL);
 }
 
 static const QEMUOption *lookup_opt(int argc, char **argv,