Fix ip-address parsing for IPv6 addresses

[jeffguy]

Sometimes, the host string uses IPv6 instead of IPv4, so the address has colons. This can result in a string like

google.com:2607:f8b0:4006:80b::200e

If we then run

subdomain, addr = host.split(":")

host.split(":") returns a list of seven strings because their are six colons. Setting (subdomain, addr) to a list of seven strings doesn't work (ValueError: too many values to unpack (expected 2)). What we really want here is

subdomain, addr = host.split(":", 1)

which splits only on the first colon, so a list of two strings is returned, and the whole IPv6 address gets assigned to the addr variable.

[L1ghtn1ng]

Thank you for submitting this, much appreciated ☺️