[nova][ops] Removing Debug middleware
There's a Debug middleware in nova that's not used in the codebase since
2010, so we're removing it .
Theoretically, deployments could be making use of it by injecting it
into the paste pipeline (a ~3LOC edit to your local api-paste.ini). If
this is you, and you're really relying on this behavior, let us know. We
can either revert the change or show you how to carry it locally (which
would be really easy to do).