Bug 21796: Don't unlock checkouts if restriction exists but fines are below limit

Bug 21796: Don't unlock checkouts if restriction exists but fines are below limit

The checkout form will be removed if various conditions are
met: Restrictions, a fine above noissuescharge etc.

Bug 19933 changed the conditions, so a restriction will no longer
block checkouts, if the fines are below the set limit.

To test:

- Add a restriction
- Confirm the checkouts form is replaced by a message
- Add a fine below the noissuescharge limit
- Confirm that the form reappears
- Apply the patch
- Check that the checkout form is gone now
- Remove restriction - form should reappear
- Add to the fine, so it's above the limit
- Form should disappear

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>