Bug 10604: increase width of two columns in the courses table

Bug 10604: increase width of two columns in the courses table

The department and term columns in the courses table started
as varchar(20), but since they refer to authorized values, need
to be varchar(80) to match authorised_values.authorised_value.  This
patch increases the width of those columns.

To test:

[1] Create two DEPARTMENT authorised values, one whose code
    is shorter than 20 characters and one whose code is longer
    than 20 characters.
[2] Create two courses; give one course the short department and
    the other the long department.
[3] Go to the courses list.  Observe that the department column is
    displays the department name only for the short course.
[4] Apply the patch.
[5] Edit the course with the long department and assign that long
    department to it again.
[6] Go back to the courses list.  Observe that both of the courses
    now display their assigned department.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Verified changes are consistent for new installations
and updated installations.
Passes all tests.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>