TDBSAM update code from Aur?lien Degr?mont <adegremont@idealx.com>.

TDBSAM update code from Aur?lien Degr?mont <adegremont@idealx.com>.
Adds support for an additional field (uint32) which represents the
lockout duration. I think this should be stored as an abolute
UNIX time_t that specifies when the lockout should end - set it
when the lockout is imposed. This new code also updates the on
disk tdb version on load. Being merged into HEAD so Simo can
add any other changes he wants before being back-ported to
SAMBA_3_0.
Jeremy.