CVE-2014-8143:auth: Force talloc type of session_info pointer to match

This helps us keep things safe in LDB where we put this in a opaque pointer.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10993

Andrew Bartlett

Change-Id: I46fe53ba655ca0810c276b72fbca524884cdf22d
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
