builtin/update-index.c: cleanup update_one
do_reupdate calls update_one with a cache_entry.name, there's no need for
the extra sanitation / normalization that happens in prefix_path.
cmd_update_index calls update_one with an already prefixed path, no need to
prefix_path twice.
Remove the extra prefix_path from update_one. Also remove the now unused
'prefix' and 'prefix_length' parameters.
As of
d089eba "setup: sanitize absolute and funny paths in get_pathspec()",
prefix_path uncoditionally returns a copy, even if the passed in path isn't
changed. Lets unconditionally free() the result.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>