Embrane Plugin Support

Implements blueprint embrane-plugin-support

This commit implements Embrane's Neutron plugin installation support
in Devstack.
This is an extension of the openvswitch installation module, which is
used by the main plugin, and enables configuration by localrc

Change-Id: Ia4824f8d2300bcdce170d226145bbce6088f1557
s3_token has been moved to keystoneclient.

Change-Id: I6ffe756d517d11f323bd0c5d3b877d9a9f739a3b
Merge "Embrane Plugin Support"
Merge "s3_token has been moved to keystoneclient."
Merge commit 'refs/changes/71/70571/2' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch
Merge commit 'refs/changes/99/70999/4' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch