upload-pack: pass upload_pack_data to upload_pack_config()

upload-pack: pass upload_pack_data to upload_pack_config()

As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to upload_pack_config(),
so that this function can use all the fields of the struct.

This will be used in followup commits to move static variables
that are set in upload_pack_config() into 'upload_pack_data'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>