If fast-import was not run with --export-marks but we are crashing
the frontend application developer may still benefit from having
that information available to them.  We now include the marks table
as part of the crash report if --export-marks was not supplied on
the command line.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>