When there are large numbers of refs, calling read_ref for each ref is
inefficent (and infact downright slow) - so instead use for_each_ref
to build up a string list of all the refs that we currently have,
which significantly improves the volume.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>