Remove last parts of Quantum compatibility shim

Goodbye Quantum!

Change-Id: Idbd0384a892beaff3a937444f04cfc433cb805eb
Closes-Bug:1299046
Explicitly import state_path opt in tests.base

This wasn't explicitly needed in the unit tests because
neutron.common.config was already loaded, but this broke for the
functional tests (which are non-voting) so add a CONF.import_opt line so
functional tests know where to find the definition for state_path.

Change-Id: I5b87a75317e2ba670adaa59b251bfa860920fd61
Merge "Remove last parts of Quantum compatibility shim"
Merge "Explicitly import state_path opt in tests.base"