Update to d2to1 0.2.10.
Update to d2to1 0.2.10.

We fixed a string bug upstream which was released, and also added some
additional backwards_compat options.

Change-Id: I636a47952a90e6e0df864dbdc9243b77eeb6d77e
Reviewed-on: https://review.openstack.org/26968
Reviewed-by: Jeremy Stanley <98883b97e35b7bb1ac282bb863f2e9d917db0454@yuggoth.org>
Approved: Clark Boylan <635fc31d01fa593720982fa0568e87170cedbe2c@gmail.com>
Reviewed-by: Clark Boylan <635fc31d01fa593720982fa0568e87170cedbe2c@gmail.com>
Tested-by: Jenkins

openstack-attic/oslo.version,emonty/oslo.version