Fix wrong use of middleware context in hypervisor.

[evanlinjin]

Fixes #58

Changes:

• Fix wrong use of middleware context in hypervisor.

[Senyoret1]

@evanlinjin This appears to be working well, I was able to remove transports without issues. However, there is a problem with the routes: until now I have been removing the routes by calling DELETE /api/nodes/{pk}/routes/{routeId} sending as the routeId param the value named key returned by the GET /api/nodes/{pk}/routes API endpoint, but that appears to not be working anymore. When I do that, the DELETE /api/nodes/{pk}/routes/{routeId} API endpoint returns {"error":"invalid UUID length: 0"}, so I think it is now expecting a different value, the problem is that I don't know were to get that value from, as the GET /api/nodes/{pk}/routes API endpoint does not return it, or at least not in a evident way.

Maybe a new issue should be filed for this problem, but I don't know what the sollution should be, if adding the param to the GET /api/nodes/{pk}/routes API endpoint, or making the DELETE /api/nodes/{pk}/routes/{routeId} acept the key param returned by GET /api/nodes/{pk}/routes, or something else.