Bug 17237: Remove CREATE USER 'user'@'%' line

Bug 17237: Remove CREATE USER 'user'@'%' line

Having a 'user'@'%' line decreases database security.
Bug 16690 closes the need for such a line, and this
bug removes the use of it.

TEST PLAN
---------
While this depends on 16690, it is not required for testing.

On a kohadev box:
sudo koha-create --create-db test_17237_a
git bz apply 17237
sudo perl ~/misc4dev/cp_debian_files.pl
restart_all
sudo systemctl daemon-reload
sudo koha-create --create_db test_17237_b
sudo mysql -u root
SELECT user,host from mysql.user;
-- test_17237_a will have two entries, one being '%'
-- test_17237_b will only have one entry, not '%'

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 1e856e7e7316749f59cb4e721e352b0a60237def)

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>