templates/login: Remove duplicate client IP address

In commit ba5de4b ("templates/login: Display the clients IP address") we
started displaying the clients IP address on the login page. This of
course required pasing the env_vars.remote_addr variable (as 'rip') to
the login template.

However we were already doing this in some situations with commit
d63319f ("Enable per user IP address access control") when a user failed
their IP ACL check.

No point passing the same thing through twice, so remove the passing of
the variable in the IP ACL check case and use the 'rip' template
variable for the IP ACL message.

Signed-off-by: Andrew Clayton <andrew@dnsandmx.com>