Disallow subnet with IPv4 special-purpose address

IANA IPv4 Special-Purpose Address Registry defines a list of reserved address.
Except private IP address, the rest of the list should not be used to configure a subnet.
Also, multicast address 224.0.0.0/4 should not be used to configure a subnet.

Closes-rally-bug: DE1363
Not-in-upstream: true
Merge pull request #56 from CiscoSystems/de1363

Disallow subnet with IPv4 special-purpose address