Pass expected_attrs to instance_get_active_by_window_joined

This change sends the expected_attrs from the instance object
API down into the DB API so the client can filter on which
columns he actually needs to join when getting all instances
in a given time window.

The simple-tenant-usage API and _instance_usage_audit periodic
task are the only things calling this API and they already
provide specific expected_attrs so there is no risk of
regression due to the change. The DB API is backwards
compatible if columns_to_join is None, and expected_attrs
defaults to None already.

Change-Id: I3d8b5a1fd58783e465001bb5f10b5b87d69198d9
Partial-Bug: #1383469
initialize objects with context in cells

These changes aim to clean up the pattern of passing a context in
object member functions create/destroy/refresh/save and instead
initialize the object with the context when it's constructed.

Related to blueprint kilo-objects

Change-Id: I5a7e3c1da6f9e2efaf296dd392e5ce9942c5729c
initialize objects with context in server groups api

These changes aim to clean up the pattern of passing a context in
object member functions create/destroy/refresh/save and instead
initialize the object with the context when it's constructed.

Related to blueprint kilo-objects

Change-Id: Ieb405b5cf8de40024a175771fba2f4c296af9e78
initialize objects with context in resource tracker

These changes aim to clean up the pattern of passing a context in
object member functions create/destroy/refresh/save and instead
initialize the object with the context when it's constructed.

Related to blueprint kilo-objects

Change-Id: I47c25c144d1f970781d6288073041501966f0178
initialize objects with context in compute api

These changes aim to clean up the pattern of passing a context in
object member functions create/destroy/refresh/save and instead
initialize the object with the context when it's constructed.

Related to blueprint kilo-objects

Change-Id: I3781bd5fb7de0ff578ea4342be5cb68eef52c43d
hardware: clean test to use well defined fake flavor

Removes FakeFlavor and FakeFlavorObject to use objects.Flavor
which what hardware methods are expected to use.
Aslo this will help to move some tests from hardware to
objects.

Change-Id: Ic08c9cf0d9147afd7ef2a3d7742960cba6817046
Remove Python 2.6 classifier

Nova does not support Python 2.6 anymore starting with Kilo and might
not work correctly with it, so remove the classifier.

Change-Id: If60c60af9ae28ce91bdcc3f7f47c906ec8250dd1
dummy patch to let tox functional pass

Tox functional job currently will fail because there are no tests,
which is makes it a little hard to atomically turn on voting with the
test move. To trick the system we can make tox functional always pass,
then change the tox definition to the real thing during the sideways
move.

Part of bp:functional-tests-for-nova

Change-Id: Ic276522851fba6d1d95dd1f3bdde1d48935568a3
Merge "Pass expected_attrs to instance_get_active_by_window_joined"
Merge "Remove Python 2.6 classifier"
Merge "dummy patch to let tox functional pass"
Merge "hardware: clean test to use well defined fake flavor"
Merge "initialize objects with context in cells"
Merge "initialize objects with context in server groups api"
Merge "initialize objects with context in resource tracker"
Merge "initialize objects with context in compute api"