Bug 10676: Fix behaviour of OpacHiddenItems for items.restricted

Bug 10676: Fix behaviour of OpacHiddenItems for items.restricted

The numerical restricted value was overwritten in GetItemsInfo
with the description. So OpacHiddenItems would only work for
restricted using the description, not the numerical value
of the authorised value like for other similar status fields.

This changes GetItemsInfo to use a separate variable for
the description, as it's already done for notforloan and
changes the template files where the variable is used
accordingly.

To test
- Before applying patch
- Configure OpacHiddenItems with:
  restricted: [1]
- Find a record with more than one item and mark one of the items
  as "Restricted Access"
  (assume standard sample data - check authorised value if status doesn't exist)
- Verify the item is still shown in OPAC.
- Apply patch
- Verify that the item is now hidden
- Verify that the status still displays nicely in the staff detail page
- Delete OpacHiddenItems
- Verify that the status is showing nicely in the OPAC detail page

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>