Merge branch 'cc/sha1-file-name' into next

Code clean-up.

* cc/sha1-file-name:
sha1_file: improve sha1_file_name() perfs
sha1_file: remove static strbuf from sha1_file_name()

diff --cc cache.h
Simple merge

diff --cc http.c
Simple merge

diff --cc sha1_file.c
Simple merge