[PATCH] lib: debug: Avoid negative array access.

[Martin Schwenke]

On Mon, 17 Apr 2017 15:44:43 -0700, Jeremy Allison via samba-technical
<samba-technical at lists.samba.org> wrote:

> Fix for bug https://bugzilla.samba.org/show_bug.cgi?id=12746.
> 
> Please review and push if happy !

Reviewed-by: Martin Schwenke <martin at meltin.net>

Happy for someone to push in batch with other stuff... if I don't see
it go then I'll push tomorrow morning...  :-)

peace & happiness,
martin