vpnor: Configure a handler table in init_vpnor()

Currently the table just mirrors that which is set by the regular
implementation, however getting to that point requires massaging the
code a little. Thus, separate out this change from one that changes the
behaviour of the commands to improve the readability of the latter
change.

Change-Id: I4007a8a4d508c6d850b8cc878bab8f72bd343498
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/vpnor/mboxd_msg.hpp b/vpnor/mboxd_msg.hpp
new file mode 100644
index 0000000..7485c38
--- /dev/null
+++ b/vpnor/mboxd_msg.hpp
@@ -0,0 +1,5 @@
+extern "C" {
+#include "mbox.h"
+
+extern const mboxd_mbox_handler vpnor_mbox_handlers[NUM_MBOX_CMDS];
+};