Simplify datastores.

Remove methods, save method deals with these cases:

* lock_person
* unlock_person
* lock_account
* unlock_account
* set_account_shell

account.lock and account.unlock updates login_enabled. Actual work in
account.save.

account.deactivate updates date_deleted. Actual work in account.save.

person.lock and person.unlock updates login_enabled. Actual work in
person.save

Change-Id: Ica540dc29c3d292fea6854422ddc1672feba3da4