When fetching changes from a depot using a full client spec, there
is no need to perform as many queries as there are top-level paths
in the client spec. Instead we query all changes in chronological
order, also getting rid of the need to sort the results and remove
duplicates.
Signed-off-by: Sam Hocevar <sam@hocevar.net> Signed-off-by: Luke Diamand <luke@diamand.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>