Remove duplicated comment (fallout of Juno config update)
Add new attribute "allow_overlapping_ips"

It directly maps to the "allow_overlapping_ips" setting in neutron.conf.
We don't want this exposed in the UI, because only very few users will want to
touch this.
Merge pull request #169 from rhafer/overlapping_ips

Add new attribute "allow_overlapping_ips"