Nova instance group DB support

DB support for blueprint instance-group-api-extension

Change-Id: I615af9826ef61fd63d4cd8017908f943969bf177
xenapi: ensure instance metadata always injected into xenstore

It is possible to use the agent, cloud-init and config drive
together on a single server. In this case we should still
be injecting the instance metadata.

The current code is inconsistent between spawn and migrations.

The correct approach is to always inject the data into xenstore.

fixes bug 1188618

Change-Id: I253b34234544cff353985a5b53ec084ea332535a
Rename functions in nova.compute.flavors from instance_type

Second step in removing references to instance_types. Remove all
references to instance_type in nova.compute.flavors.
Also update compute devref to reflect changed name.
Partially implements bp flavor-instance-type-dedup

renamed:  nova/tests/test_instance_types.py -> test_flavors.py

Change-Id: I7413bf832c61d04ab90ec8b1370d3f01372c4172
Merge "Nova instance group DB support"
Merge "xenapi: ensure instance metadata always injected into xenstore"
Merge "Rename functions in nova.compute.flavors from instance_type"