Updated openstack/openstack
Project: openstack/neutron  2bebeec6c93f196720c3368f29e09a77546a646b

Check DB scheme prior to migration to Ml2

When using migration tool from LB/OVS plugin to Ml2, there is no
guarantee current scheme is supported by migration tool. This patch
checks version stored in DB by alembic and compares whether version
is supported.

Closes-bug: #1307720

Change-Id: I4519a0e5a0f3027675958a68d1f9e0440b177229