functional._make_request: go back to simple version of httplib.request.

functional._make_request: go back to simple version of httplib.request.

The httplib.request function automatically constructs the following
headers:
content-length, host, accept-encoding

Until such time as we need to override those values in incompatible
ways, simply use it.

Fixes: https://github.com/ceph/s3-tests/pull/92#issuecomment-185970260
Signed-off-by: Robin H. Johnson <robin.johnson@dreamhost.com>