Bug 37104: Block AnonymousPatron from logging into staff interface and OPAC

Bug 37104: Block AnonymousPatron from logging into staff interface and OPAC

This patch blocks the patron set as the anonymous patron from logging into the staff interface and OPAC.

To test:
1) In Administration->sys. pref, make sure AnonymousPatron is pointed to an account.
2) Visit that patron's page and set their permissions to superlibrarian ("Access to all librarian functions")
3) Ensure that you know the username and password for this patron and can log in.
4) Visit the OPAC, attempt to log-in with your anon patron.
5) Note that you can log in and nothing happens.
6) Visit the staff interface, attempt to log-in with anon patron.
7) Once again, note that you are able to log-in with no issue.
8) Apply patch and restart_all
9) Attempt to log into the OPAC and staff interface with the patron again.
10) This time, you should get an error message on both pages saying, "Error: You can't log in as the anonymous patron!"

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>