Incorrect idp.pool.LDAP.validatePeriod property format

[Rod Widdowson]

We should probably build a factory bean (or is it a bean factory?) to
generate these third party entities when they can take durations.  Then the
setter can take an @Duration long..

> I thought about it, but it's tricky. Since there's no standard for
> this, it would have to be a separate Duration annotation and converted,
> or we'd have to switch to a common one.

I'll add an RFE when I get back to my desk after the Holidays.

Rod