Some network protocols (e.g. native git://) are able to fetch more
than one ref at a time and reduce the overall transfer cost by
combining the requests into a single exchange. Instead of feeding
each fetch request one at a time to the helper, feed all of them
at once so the helper can decide whether or not it should batch them.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org> CC: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>