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
If n-api-meta is being run, remove from NOVA_ENABLED_APIS

If running n-api-meta as a separate service we shouldn't run it inside
of n-api. This patch is in support of Iddd44f7ee43b9287a788dea49eaa484316f8da04

Change-Id: I8a54cf13dc6083b78e89c9ea5413d9e4d8d4b37a
Related-Bug: #1270845
Merge "If n-api-meta is being run, remove from NOVA_ENABLED_APIS"
Merge "Embrane Plugin Support"
Merge "s3_token has been moved to keystoneclient."