Cleanup v2.1 controller inheritance

For microversions support to work all the API controllers must
inherit from wsgi.Controller rather than object. Currently most
do inherit from wsgi.Controller but some don't. This patch
ensures that all do so.

Partially implements blueprint api-microversions

Change-Id: Ic7351298ae96aa7bb509eb3784e672d5feea262a
Merge "Cleanup v2.1 controller inheritance"