Use common get_instance call in API plugins part 3

Cleanup v2.1 API to use common get_instance call which
automatically does exception handling. Although most of
the v2.1 API was cleaned up a while back, some recent
ports of v2 API code has resulted in some cases creeping
backing in.

Change-Id: I8271a2805fe9fdfae40df43183a5251fddbe4c13
Adapting pylint runner to the new message format

Pareseable output format and --include-ids parameter are deprecated
and ignored in the pylint version used on the gate.
These functions are replaced by the --msg-template parameter.

This patch changes the runner to use the new parameter so that the
job can run properly on the gate

Closes-Bug: #1394606
Change-Id: I1de424bae4c2b634cd0bc804cb7e81624c96a195
Remove havana compat from nova.cert.rpcapi

Since we only support upgrading from N-1 to N, there's no need to keep
around this older upgrade related code.

Change-Id: Ie13f98da84f3d631efea2670fbc926b69b405284
Adds new RT unit tests for _sync_compute_node

Adds new unit tests for the resource tracker's _sync_compute_node()
method. These new unit tests should make the objectification of the
resource tracker easier to do, since the old unit tests in
test_resource_tracker.py are brittle and hard to change.

Change-Id: I3e8d179d8c3856084fee595c8b0396a8a5db8aa4
Blueprint: make-resource-tracker-use-objects
Merge "Adapting pylint runner to the new message format"
Merge "Use common get_instance call in API plugins part 3"
Merge "Adds new RT unit tests for _sync_compute_node"
Merge "Remove havana compat from nova.cert.rpcapi"