Add a flexible API version choice for Cinder, Glance and Heat

The version of the authentication url is set to v1.0 for some
projects by default. We can make it configurable via the parameter
"$IDENTITY_API_VERSION".

Closes-Bug: #1253539
Change-Id: I6640e345d1317b1308403c95b13f8a998320241b
Use --tenant-id, not --tenant_id

Change-Id: I0e3d65d5b69ac82cbf7ee6ffc41ead369af8c126
Merge "Use --tenant-id, not --tenant_id"
Merge "Add a flexible API version choice for Cinder, Glance and Heat"
Merge branch 'master' of github.com:openstack-dev/devstack