This should allow you to disable completely Ipv6:
Add these lines to the bottom of sysctl.conf
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
Then run sudo sysctl -p or reboot
source: http://www.noobslab.com/2012/05/disable-ipv6-if-your-internet-is.html
This of course won't stop bind from blindly trying to use ipv6 though, so you also need to alter /etc/default/bind9 like so:
# run resolvconf?
RESOLVCONF=yes
# startup options for the server
OPTIONS="-4 -u bind" -
source: http://blog.evilcoder.net/disable-ipv6-on-bind9-linux/#sthash.U95y4s6U.dpuf
