This is done by renaming many functions and some variables to
remove "skip" in the name, and by adding a
"struct sha1_array *array" argument where needed.
While at it, make the second argument to "lookup_sha1_array"
const. It becomes "const unsigned char *sha1".
Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>