Bug 24772: Don't revert course item fields when deleting a course item unless it...

Bug 24772: Don't revert course item fields when deleting a course item unless it is enabled

Deactivating a from Course Reserves reverts Item's Shelving Location
correctly, then deleting the same course reverts the Course Reserve
Items to old shelving location values.

Test Plan:
1) Add items to a Course - make sure they all have shelving locations
prior to being added to the course.
2) When adding items change their shelving location to something else.
   See that Shelving Location has changed; permanent location in
parentheses
3) Deactivated course
   See that Shelving Location has changed back to its original location
4) Deleted course
   See that Shelving Location has changed back to what was picked during
adding it to the Course.
5) Apply this patch, restart all the things!
6) Repeat steps 1-4, note the shelvig location is not lost!

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Hannah Olsen <holsen@duncanville.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>