The parent of this patch introduced the change to Alembic-based
migrations. This commit builds on top of that by adding expand,
migrate and contract commands to the glance-manage tool.
Appropriate documentation is updated and failing tests are adjusted
to accomodate the new database versioning schema.
Data migrations are expected to be run in the background with older
Glance services being active during the upgrade process.
Partially-Implements: blueprint database-strategy-for-rolling-upgrades
Co-Authored-By: Hemanth Makkapati <hemanth.makkapati@rackspace.com>
Change-Id: Ie839e0f240436dce7b151de5b464373516ff5a64
Depends-On: I77921366a05ba6f9841143af89c1f4059d8454c6