Merge branch 'mh/object-code-cleanup'

* mh/object-code-cleanup:
sha1_file.c: document a bunch of functions defined in the file
sha1_file_name(): declare to return a const string
find_pack_entry(): document last_found_pack
replace_object: use struct members instead of an array

diff --cc cache.h
Simple merge

diff --cc http.c
Simple merge

diff --cc sha1_file.c
Simple merge