Add workaround for IPv6 parsing

[mp911de]

Redis reports IPv6 addresses as bare IP address even when provided with a port:

ASK redirection

-ASK 1234 dead:beef:dead:beef:1:2::3:6379

CLUSTER NODES output

c37ab8396be428403d4e55c0d317348be27ed973 affe:affe:123:34::1:7381 master - 111 1401258245007 222 connected 7000 12000 12002-16383

The lack of brackets causes some ambiguity but in the mentioned cases we know the expected format so we can work around the issue by introducing compatibility parsing until https://github.com/antirez/redis/issues/3076 gets resolved.