Revert "neutron: Update to stable/havana"

This reverts commit d7a3f2ad9ab687aea276af95bc75477a97700ddd.
Revert "Neutron: do not specify agent_down_time without report_interval"

This reverts commit 393321302a4764a6477c95c60964e71e13985a60.
Neutron: set report_interval to old default value
Merge pull request #473 from blueboxgroup/revert-neutron-changes

Revert neutron changes