rest/test.py: earlier versions of requests.py don't quote ' ' in params

requests 0.12.1 handles queryparams in the URL with embedded
spaces; requests 0.8.2 does not.  Avoid the issue by quoting the
URL into expect().

Signed-off-by: Dan Mick <dan.mick@inktank.com>
ceph_rest_api.py: reversed test for failed request

A failed request has a response code *outside* the range (200, 300],
not within it.

Signed-off-by: Dan Mick <dan.mick@inktank.com>