Don't store http responses from paginated results

This is really bad if you are paginating over a large
set of data (like s3 objects).

This was previously used to check for error responses, but this
is no longer used by anything.  The error handling is all event
based now (via `after-call` events).
Merge branch 'dont-store-page-responses' into develop

* dont-store-page-responses:
  Don't store http responses from paginated results
Add the VirtualizationType parameter to RegisterImage operation.  Fixes #132.
Fix whitespace issue in JSON.
Merge branch 'ec2-register-image-virt-type' of git://github.com/garnaat/botocore into garnaat-ec2-register-image-virt-type