format-patch --attach/--inline uses filename not SHA1

This patch series modifies the behavior of format-patch when used with the --attach or --inline command line settings. Current behavior names the attached or inlined patches with the SHA1 of the commit, which isn't very friendly or easy for a human to use when downloading the attachments. This series replaces the SHA1 values with the filename used by format-patch when it outputs the patches to files.

New features in this version:
- %f format specifier exposing sanitized filenames to porcelain
- get_patch_filename() moved to log-tree

Stephen Boyd (6):
pretty.c: add %f format specifier to format_commit_message()
format-patch: construct patch filename in one function
format-patch: pass a commit to reopen_stdout()
format-patch: move get_patch_filename() into log-tree
format-patch: --attach/inline uses filename instead of SHA1
format-patch: --numbered-files and --stdout aren't mutually exclusive

 Documentation/pretty-formats.txt                   |    1 +
 builtin-log.c                                      |  132 +++++----------
 log-tree.c                                         |   41 ++++-
 log-tree.h                                         |    6 +-
 pretty.c                                           |   38 +++++
 revision.h                                         |    2 +
 t/t4013-diff-various.sh                            |    3 +-
 ..._--attach_--stdout_--suffix=.diff_initial..side |   61 +++++++
 ....format-patch_--attach_--stdout_initial..master |   12 +-
 ...format-patch_--attach_--stdout_initial..master^ |    8 +-
 ...ff.format-patch_--attach_--stdout_initial..side |    4 +-
 ...nline_--stdout_--numbered-files_initial..master |  170 ++++++++++++++++++++
 ...tdout_--subject-prefix=TESTCASE_initial..master |   12 +-
 ....format-patch_--inline_--stdout_initial..master |   12 +-
 ...format-patch_--inline_--stdout_initial..master^ |    8 +-
 ...ormat-patch_--inline_--stdout_initial..master^^ |    4 +-
 ...ff.format-patch_--inline_--stdout_initial..side |    4 +-
 17 files changed, 389 insertions(+), 129 deletions(-)
 create mode 100644 t/t4013/diff.format-patch_--attach_--stdout_--suffix=.diff_initial..side
 create mode 100644 t/t4013/diff.format-patch_--inline_--stdout_--numbered-files_initial..master