OVH instances are getting ipv6 addresses now. This is great except that
the only info on these addresses seems to be in the nova/neutron api and
not via ipv6 router advertisements or config drive metadata. Until we
sort out a programmatic way to configure ipv6 on the instances at boot
lets not attempt to use ipv6 when connecting to OVH instances.
Change-Id: I48e773b9f29fae9a15f6c95fc64831ab0749cc60
cb51d5b332