enable "no-done" extension only when serving over smart-http
Do not advertise no-done capability when upload-pack is not serving over
smart-http, as there is no way for this server to know when it should stop
reading in-flight data from the client, even though it is necessary to
drain all the in-flight data in order to unblock the client.
Signed-off-by: Junio C Hamano <gitster@pobox.com> Acked-by: Shawn O. Pearce <spearce@spearce.org>