Organize limits units and per-units constants

During v3 api review there was an agreement that would be nice to move limits
constants to utils file and refactor its usage inside limits api to avoid
unnecessary code duplication.

Also changed TestLimiter class to MockLimiter since that name can be confuse to
some unit test frameworks.

Change-Id: I1b8626e8d1e3257333d4dfee61591fd4cde82bd1
Log xml in libvirt _create_domain failures

When an error occurs defining, launching or enabling hairpin mode on a
libvirt domain, log the xml for reproduction and analysis.

Fixes bug 1183534

Change-Id: Ic8f1d11c5a92779c686b7248895bbc6f2cfdbf0b
Sync db.models.Quota* with migrations.

Blueprint: db-sync-models-with-migrations

Change-Id: Ic97690b650151eb7086cbd40093c0f3c373133e2
Baremetal_deploy_helper error message formatting.

Updates our baremetal_deploy_helper so our error message use
formatting that works with translations.

Change-Id: I8811df50f0e80c5680e6316c829a197b0ade5967
Port flavor_access extension to v3 API Part 2

Ports the flavor_access extension and the corresponding
unittests to the v3 framework.

Partially implements blueprint nova-v3-api

Change-Id: I671f490bad2daaaae06d48328f4fff10076ab0ed
Sync to_primitive() IPAddress support from Oslo

This enlightens to_primitive() that it may just call str() to
serialize netaddr.IPAddress objects.

We need this for NovaObject serialization through legacy interfaces
temporarily while we migrate things.

Related to blueprint unified-object-model

Change-Id: Ibdee90e4bbd337d541344977e2a689982e0a7d34
Fix metadata access in prep for instance objects

Related to blueprint unified-object-model
Fixes: bug #1192012

Change-Id: I8b708dc3d89fedfcb4bbf5d26b959da1298b0525
Merge "Port flavor_access extension to v3 API Part 2"
Merge "Log xml in libvirt _create_domain failures"
Remove trivial cases of unused variables (3)

Kill some of the variables marked as unused by flakes8. This should
allow to enable F841 check in the future.
Only trivial cases with no function calls and obviously pure functions
(like datetime.now(), or len()) are cleaned up here.

Part 3, split to reduce conflicts.

Change-Id: I7b8e806ddd7b0e077243d4e31de140cd08fe0155
Merge "Sync db.models.Quota* with migrations."
Merge "Organize limits units and per-units constants"
Merge "Baremetal_deploy_helper error message formatting."
Merge "Fix metadata access in prep for instance objects"
Merge "Remove trivial cases of unused variables (3)"