Split rjil::neutron into a contrail and an ovs variant

We still use OVS in the undercloud (only for PXE, it's not in the
critical path of any network traffic)
Update tests related to neutron split
Merge pull request #266 from bodepd/decouple_neutron

Decouple neutron
Turn undercloud behemoth into beautiful Ironic component
Create DB for Neutron (will not be used by contrail, only OVS)
Compose uc role of common components