Comment 23 for bug 1780348

The bug fix to set sysctl defaults on the Neutron Gateway the has broken Openstack on LXD as the variables are not available in containers, see https://ask.openstack.org/en/question/121359/error-neutron-gateway-in-openstack-on-lxd/. The workaround is to set the value to "" explicitly in the bundle so that they are set by the user rather than the defaults.