This is a macro that sets the pointer to NULL after the talloc_free()
and is part of our standard coding practices.
Signed-off-by: Andrew Bartlett <abartlet@samba.org> Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
(cherry picked from commit 2117789c35fbf6d0ed02f391f17593e11727ec3e)