Read flavor even if it is already deleted

Currently libvirt code has some references to Flavor
as objects.Flavor.get_by_id. because the flavor might be
deleted before it's referenced, so most code need to
read deleted flavor in libvirt driver. This patch
makes the _prepare_args_for_get_config which is used for
sriov feature consistent to other Flavor get functions.

Related-Bug: #1352668

Change-Id: Ia4a03467720f1fed18cabe1b78bdd4488f316e34
Split out IO Ops filter unit tests

Break out the unit tests for IO Ops filters from test_host_filters.py
into its own file. In the process, we mock out the database calls for
getting aggregate information instead of creating database records.

Change-Id: I8395ba7c09ca5c85ecd94d2cc670f3cd0880a373
Split out core filter unit tests

Break out the unit tests for core filters from test_host_filters.py
into its own file. In the process, we mock out the database calls for
getting aggregate information instead of creating database records.

Change-Id: I9c602b9832632ad84b4b0941c5254a283d278b69
Split out aggregate disk filter unit tests

The aggregate disk filter unit tests remained in test_host_filters.py,
and this patch moves them to the test_disk_filters.py file. This was the
last occurrence of aggregate database calls from test_host_filters.py.

Change-Id: Ic47c41474dce8bf3936910be5feee081445193de
Change error code of floating_ip_dns api(v2.1)

Changes :
webob.exc.HTTPUnprocessableEntity(422) -> webob.exc.HTTPBadRequest(400)

Partially implements blueprint v2-on-v3-api
Change-Id: Ic6063c2c4525c7ff8e07495c75c134ff7e78756b
Merge "Read flavor even if it is already deleted"
Merge "Change error code of floating_ip_dns api(v2.1)"
Merge "Split out IO Ops filter unit tests"
Merge "Split out core filter unit tests"
Merge "Split out aggregate disk filter unit tests"