The version of the neutron package currently in unstable and stretch (9.1.1) is incompatible with the version of vmware-nsx in unstable (8.0.0). During the Newton release cycle, Neutron was changed to move SecurityGroup from:
neutron.db.securitygroups_db to: neutron.db.models.securitygroup For the specific line of code failing in this FTBFS, see this change that was made in the 9.1.0 release of vmware-nsx: https://anonscm.debian.org/cgit/openstack/vmware-nsx.git/commit/?h=debian/newton&id=4950717f9550732f6655c97afda07ed401a37a0d The fix for this bug is to package a compatible version of vmware-nsx. Apparently the 9.1.0 package of vmware-nsx was created, but never uploaded to unstable: https://anonscm.debian.org/cgit/openstack/vmware-nsx.git/log/?h=debian/newton Allison
