Set parameters for OpenDaylight ML2 driver

Now that https://review.openstack.org/#/c/85589/ is merged, the
OpenDaylight ML2 driver requires that url, username and password
parameters are set.

Change-Id: Iecbdd3275387bea145a5d274d359a15eceaee6b7
Closes-Bug: #1304226
Revert "Devstack support for Neutron VPNaaS"

This reverts commit 8450a92a4d0299fff89717e665ce31d54731d3f0.

Change-Id: I6dd0f44a1a57735de292bc4ed4eaa929dc308297
Merge "Set parameters for OpenDaylight ML2 driver"
Merge "Revert "Devstack support for Neutron VPNaaS""
Merge branch 'master' of https://github.com/openstack-dev/devstack