Bug 24711: Don't add logout input to login form

Bug 24711: Don't add logout input to login form

To test:
1 - Set OpacPublic syspref to 'Disable'
2 - Log in to OPAC
3 - Log out
4 - Try to log in again
5 - No error, but you get the login form again
6 - Apply patch
7 - Repeat
8 - This time you can log in again

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Joy Nelson <joy@bywatersolutions.com>