[Dovecot] Eronious comment in sample Director configuration

[Brad Davidson]

The sample Director configuration (10-director.conf) says that
director_servers and director_mail_servers can be lists of either IPs or
hostnames:

# List of IPs or hostnames to all director servers, including ourself.
# Ports can be specified as ip:port. The default port is the same as
# what director service's inet_listener is using.
#director_servers =

# List of IPs or hostnames to all backend mail servers. Ranges are
allowed
# too, like 10.0.0.10-10.0.0.30.
#director_mail_servers =

However, if I use hostnames, it bails out with an "Invalid IP address"
error. It also seems to be confusing the dashes in my hostnames for
address range specifications.

Obviously hostnames are not currently supported, but I thought I'd
mention it so the documentation could be updated.

-Brad