man: Fix consensus timeout

The consensus timeout is 1.2 * token_timeout,
which has been changeg from 1000 to 3000, so change also consensus
timeout.

Signed-off-by: miharahiro <hmihara@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>