Bug 24379: Make login_attempts not nullable

Bug 24379: Make login_attempts not nullable

While the column defaults to 0 in Koha::Object->store we set to NULL if NULLABLE

When trying to reset a patrons password we check that the account is not administratively locked:
login_attempts != -1

This query does not return rows where login_attempts IS NULL. It will return accounts where login_attempts = 0

Let's default to 0 like we intend

To test:
1 - Create a new patron
2 - Note their login_attempts is NULL
    SELECT login_attempts FROM borrowers ORDER BY borrowernumber DESC LIMIT 1
3 - Enable  OpacResetPassword
4 - Attempt to reset password before logging in, you cannot
5 - Apply patch, updatedatabase, restart_all, update schema
6 - Create another patron
7 - Their login attempts should be 0
8 - Attempt to reset password, it works!

Bug 24379: Fix the test

First we create a patron using TestBuilder to get a hashref of valid
info. Then we delete it and create a new patron using Koha::Patron->new
Once stored, we should call discard_changes to make the calculated
values available in the currenct object.

Bug 24379: Don't drop default of 0 for login attempts

When moving the column we drop the default, this means that DBs upgraded form earlier versions
get the wrong values set

To test:
1 - Checkout 16.11.x
2 - Reset all
3 - Checkout master
4 - updatedatabase
5 - SHOW CREATE TABLE borrowers;
6 - Note the column login_attempts defaults to NULL
7 - Apply patch(es)
8 - Repeat
9 - Now it defaults ot 0 (and has NOT NULL if applied all)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>