tcpircbot: work with IPv6 & no ACL, clarify option

tcpircbot bailed out if the address wasn't ipv4 and skipped the check
for private & loopback, although netaddr supports those methods fine for
ipv6 too. Remove that piece of code, making the behavior the same on
both ipv4/ipv6.

Also, the CIDR option isn't limited to IPv6 at all, so clarify the
puppet documentation to reflect that. While at it, use some better
examples with addresses from the reserved for documentation ranges.

Change-Id: If23b0802cb19743a40d4fecdd662964735576cea
tcpircbot: IPv4 cidr instead of IPv4-mapped IPv6

No reason to use the weird-looking IPv4-mapped instead of proper IPv4
cidr subnets. tcpircbot supports both and should do the right thing.

Change-Id: Id688a26dbf5c7142fd3b2d0bfaed9b65869c7c63