Fix bytes_sent bugs.

Fix bytes_sent bugs.

log bytes sent/received.
add cct to bufferingfilter
add cct to RGWRestfulIO
AccountingFilter - save cct for debugging output
implement AccountingFilter::complete_request() - account for bytes reported here.
BufferingFilter<T>::complete_request() - ignore counts from send_content_length() complete_header();

Code quality note:
this patch makes "cct" available for a lot of newly added debug
statements.  The debug statements are mostly not very useful (and should
go away in the future) - *But* the "cct" logic should be redone and
incorporated into some base class (such RestfulClient) so that it is
possible to easily add in debug statements such as these in the future.

Fixes: http://tracker.ceph.com/issues/19870
Signed-off-by: Marcus Watts <mwatts@redhat.com>