Bug 20177: [sql_modes] Fix GROUP BY clause in GetCourses

Bug 20177: [sql_modes] Fix GROUP BY clause in GetCourses

Fix for:
'koha_kohadev.courses.department' isn't in GROUP BY

t/db_dependent/CourseReserves.t

A better fix would be to remove the joins and only return values from
the courses table. But more work is needed to acchieve that goal.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Test passes and the behavior of Course reserves appears to be unchanged
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>