replace tcp://host with tcp://[host] for IPv6 compatibility

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
listen on ipv6 as well as ipv4

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
try ip address as ipv6 if ipv4 failed

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>