Encode a useful name in the memory policy.

The instance name is the (essentially) randomnly generated libvirt
instance-000hex name. It is useless vis-a-vis matching with a policy for any
class of instances.

Instead, encode, the name of the blessed instance. That way, one can build
policies reasoning on properties that should apply uniformly to a generation.

Change-Id: If0c36d886b00e79a27cc0aee7f0246dcb3166541
Elevate context in the manager entry points

The main context authorization happens at the API entry point and
it is assumed by the time the request reaches the manager that it
is allowed. Unfortunately, some database methods check the context
for admin-ness. This is being phased out of OpenStack because
checks are happening at the time the request enters. To get around
these database checks, we simply elevate all contexts entering to
admin.

Change-Id: Ib01b6f7932996eb17ebea733408bebbd02d81e3f
Fetch the instance_type by id instead of flavor_id

fixes OS-125

The wrong database method was being used to fetch the instance_type
to generate the vms_policy string. Instead of retrieving it by
flavor id we get it by the instance type id directly.

Change-Id: Ice26de114f6698ad650a8c4cf8077da7728f15d3
Merge branch 'stable/essex' into stable/folsom

Change-Id: Ic58ea55203e30d3fe3688e5826a3f3cf0dc82178
Merge "Merge branch 'stable/essex' into stable/folsom" into stable/folsom