Bug 14737: wrong permissions required for cn_browser.pl plugin

Bug 14737: wrong permissions required for cn_browser.pl plugin

The cn_browser.pl cataloguing plugin only searches for used callnumbers
on the bibliographic database. There is no need for this plugin to
require special permissions besides access to the catalog.

To test:
- Link the cb_browser.pl cataloguing plugin to 952$o in your favourite cataloguing framework
- Login with a superlibrarian user
- Try the plugin
=> SUCCESS: you can use it
- Login with a user that has the full 'tools' permission
- Try the plugin
=> SUCCSES: you can use it
- Login with a user that doesn't have full 'tools' permission
  but has the normal catalogue and cataloguing permissions.
- Try the plugin
=> FAIL: you are requested to login with a different user
- Apply the patch
- Retry
=> SUCCESS: you can use it
- Sign off :-D

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>