Return complete response from limits,migration client

Currently compute limits and migration client returns Response by
removing top key from Response.
For example-
 return service_client.ResponseBody(resp, body['limits'])

As service clients are in direction to move to Tempest-lib, all
service clients should return Response without any truncation.
One good example is Resource pagination links which are lost with current
way of return value. Resource pagination links are present in parallel
(not inside) to top key of Response.

This patch makes compute limits and migration client to return complete
Response body.

Change-Id: Ice3665e91ff34409f6f105303213303d1fca1816
Implements: blueprint method-return-value-and-move-service-clients-to-lib
10 files changed