Bug 29542: Prevent access to private list to non authorized users

Bug 29542: Prevent access to private list to non authorized users

The catalogue permission is not enough.

Test plan:
Create a private list owned by user A
Login with user B and hit (with XX the shelfid)
  /cgi-bin/koha/virtualshelves/sendshelf.pl?shelfid=XX

You should get an error message "You do not have sufficient permission
to continue."

Login with user A
=> You should be able to send the list

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>