Remove kombu as a dependency for Nova

It was required before oslo.messaging.

Change-Id: I3159b8509ac5b4020cd584c894eb131bb16df97c
Make instance_get_all_*() funtions support the smart extra.$foo columns

This is a follow-on to a previous patch set that made the extra columns
valid for being specified in columns_to_join, as they require slightly
different handling.

Related to blueprint flavor-from-sysmeta-to-blob

Change-Id: Ieffec0e846565b7521fe620694d9f84c67066e11
Replace the rest of the non-object-using test_compute tests

This has some effects on both conductor task and shelve tests. The
shelve tests are overly complex and a troubling mix of objects and
raw DB, which I converted as best I could.

Related to blueprint flavor-from-sysmeta-to-blob

Change-Id: I410af5ce989555b6f7cb80676f0ed0537855b9ce
Adds API microversion response headers

Adds the following headers to REST API headers for API
microversions:

X-OpenStack-Compute-API-Version: Version
Vary: X-OpenStack-Compute-API-Version

Partially implements blueprint api-microversions

Change-Id: I5748d7b81b355bf8aad6bb8703d1a29a97798452
Add support for microversions API special version latest

Adds support for specifying 'latest' as the version of the API in
the X-OpenStack-Compute-API-Version header. This will always
behave as if a request was made for the maximum version
supported.

Partially implements blueprint api-microversions

Change-Id: Ib40b20a01991e6f356b9376f797405a4c50b7e99
Merge "Adds API microversion response headers"
Merge "Add support for microversions API special version latest"
Merge "Make instance_get_all_*() funtions support the smart extra.$foo columns"
Merge "Replace the rest of the non-object-using test_compute tests"
Merge "Remove kombu as a dependency for Nova"