"--" is used to separate pathspecs from the rev specs, and not rev
specs from the options, as the shortlog_usage string currently
indicates. In correcting this usage string, make it consistent with
the log_usage string.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>