ipa-ca-install: mention REPLICA_FILE as optional in help
As man page already does it, update the help text to show REPLICA_FILE
as optional.
Fixes https://pagure.io/freeipa/issue/7223
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>
Reviewed-By: Abhijeet Kasurde <akasurde@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>