Force Config Drive for tempest-dsvm-nova-py35 job
Running into a bit of problem with Neutron metadata agent. So let's
try switching on the config drive so instances can get their metadata.
export DEVSTACK_GATE_TEMPEST=1
export DEVSTACK_GATE_TEMPEST_FULL=1
export DEVSTACK_GATE_NEUTRON=1
+ export DEVSTACK_GATE_CONFIGDRIVE=1
# swift is not ready for python3 yet
export DEVSTACK_LOCAL_CONFIG="disable_service s-account"
