Fix IDL and OU setting check for staged users

The IDL had references to sequences that do not exist:

staging.usr_stage_row_id_seq -- a typo, fixed

In the case of staging.billing_address_stage_row_id_seq, the
staging.billing_address_stage table is created with LIKE,
and uses the sequence staging.mailing_address_stage_row_id_seq

The OU setting check for the open-ils.actor.user.stage.create API
call was not passing an org unit, and would always fail.

We now pass the home_ou of the user being staged.

At this point, the opac.allow_pending_user OU setting type must
be manually created before its value can be set.

Signed-off-by: Jeff Godin <jgodin@tadl.org>
Signed-off-by: Bill Erickson <berick@esilibrary.com>