Bug 13518: Delete patron's modifications along with the patron

Bug 13518: Delete patron's modifications along with the patron

The table borrower_modifications has no FK constraint on the borrowernumber
and will remain untouched when the patron is deleted.
If the borrowernumber doesn't exist in the database, the modification entry is no longer visible in Koha.

The problem is that this table is used for the borrower modifications and the self-registration features.

So far borrowernumber is the PK (int(11) NOT NULL DEFAULT '0'), for the self-registration feature we can have borrowernumber that is not defined (0 is used)

Ideally we would like to have borrowernumber a DEFAULT NULL, and use NULL for self-reg, but then we will loose the PK (PK cannot be NULL).

As we cannot keep the correct constraints at DB level anyway, we will need to handle consistency at code-level.

Test plan:
Create a new patron
Do some modification at the OPAC
Delete the patron
Confirm that the modifications as been removed (directly in DB)

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>