tests: Increase minPwdAge used for PSO tests

tests: Increase minPwdAge used for PSO tests

The PSO minPwdAge test was using a 1 second timeout. While this seemed
to work fine most of the time, we did see a rackspace failure that was
presumably due to the test taking longer than 1-second to execute
(which resulted in the password not being correctly rejected).

This patch increases the minPwdAge used, to try to avoid this problem
happening.

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>