Merge branch 'mm/verify-filename-fix' into maint

"git diff COPYING HEAD:COPYING" gave a nonsense error message that
claimed that the treeish HEAD did not have COPYING in it.

* mm/verify-filename-fix:
  verify_filename(): ask the caller to chose the kind of diagnosis
  sha1_name: do not trigger detailed diagnosis for file arguments

diff --cc builtin/grep.c
Simple merge

diff --cc builtin/rev-parse.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc revision.c
Simple merge

diff --cc setup.c
Simple merge

diff --cc sha1_name.c
Simple merge