Bug 22059: Fix exception params in Koha::Patron->set_password

Bug 22059: Fix exception params in Koha::Patron->set_password

This simple patch fixes a wrong call to ->throw. Parameters shouldn't be
enclosed in curly brackets.

To test:
- Apply the tests patch
- Run:
  $ kshell
 k$ prove t/db_dependent/Koha/Patrons.t
=> FAIL: Tests fail because the throw call is wrong
- Apply this patch
- Run:
 k$ prove t/db_dependent/Koha/Patrons.t
=> SUCCESS: Tests pass!
-Sign off :-D

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>