dsdb: Do not attempt to return beyond the end of the password history array

Found by AddressSanitizer

Change-Id: I82e35aea60726053c79510ba8ed3eedfaf553eb7
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Matthieu Patou <mat@matws.net>

Autobuild-User(master): Matthieu Patou <mat@samba.org>
Autobuild-Date(master): Mon Oct 13 08:28:15 CEST 2014 on sn-devel-104
lib/util: Use snprintf() instead of strftime() in timeval_str_buf()

This removes conditional code and ensures that the output is always as
expected.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Pair-programmed-with: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Volker Lendecke <vl@samba.org>
lib/util: Add RFC3339 timestamp support to timeval_str_buf()

Note that this can't be done more simply or portably with strftime(3)
since "%z" isn't portable.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Pair-programmed-with: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Mon Oct 13 12:27:04 CEST 2014 on sn-devel-104