Do not change the existing info/refs and objects/info/packs
files if they match the existing content on the filesystem.
This is intended to preserve mtime and make it easier for dumb
HTTP pollers to rely on the If-Modified-Since header.
Combined with stdio and kernel buffering; the kernel should be
able to avoid block layer writes and reduce wear for small files.
As a result, the --force option is no longer needed. So stop
documenting it, but let it remain for compatibility (and
debugging, if necessary).
v3: perform incremental comparison while generating to avoid
OOM with giant files. Remove documentation for --force.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>