Bug 6322 - It's possible to view lists/virtualshelves even when virtualshelves is off

 Bug 6322 - It's possible to view lists/virtualshelves even when virtualshelves is off

If the user knows the URL for OPAC lists they can access them even with
the virtualshelves preference turned off. This patch copies the solution
added to opac-topissues.pl by Bug 10595 and applies it to OPAC lists
pages.

To test, apply the patch and set the virtualshelves system preference to
"don't allow."

- Navigate to /cgi-bin/koha/opac-shelves.pl. You should be redirected to
  an Error 404 page.
- Also check:
  - /cgi-bin/koha/opac-shareshelf.pl.
  - /cgi-bin/koha/opac-downloadshelf.pl
  - /cgi-bin/koha/opac-sendshelf.pl
  - /cgi-bin/koha/opac-addbybiblionumber.pl
- Turn virtualshelves back on. Access to lists and list sharing should
  be restored.

Signed-off-by: Aleisha <aleishaamohia@hotmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>