various fixes for the keepalived.conf pillars
- sort alphabetically
- add missing key in pillar/secrets/role/proxy.sls
- the keys that shouldn't have arguments are supposed to have empty
value on the pillars, not True (this used to work in the past, but not
any more)
- move the smtp_alert in vrrp_instances (should be there according to
the docs)
- typo in notification_email