correctly handle IPv6 and IPv4 addresses fix #1143
correctly handle IPv6 and IPv4 addresses fix #1143

This commit correctly splits IPv6 addresses into the host and port
parts. This will work for normal IPv4 and IPv6 addresses appended by a
port number as well es for IPv6 addressess without a port, which should
be the normal IPv6 usage.

lmcro/letsencrypt,bsmr-misc-forks/letsencrypt,TheBoegl/letsencrypt,jtl999/certbot,mitnk/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt,jsha/letsencrypt,brentdax/letsencrypt,mitnk/letsencrypt,letsencrypt/letsencrypt,wteiken/letsencrypt,jtl999/certbot,DavidGarciaCat/letsencrypt,DavidGarciaCat/letsencrypt,dietsche/letsencrypt,TheBoegl/letsencrypt,wteiken/letsencrypt,dietsche/letsencrypt,jsha/letsencrypt,stweil/letsencrypt,stweil/letsencrypt,bsmr-misc-forks/letsencrypt,brentdax/letsencrypt