scandump.exp (scan-dump, [...]): Treat a missing dump file as unresolved and report the reason to the log file.

	* lib/scandump.exp (scan-dump, scan-dump-times, scan-dump-not,
	scan-dump-dem, scan-dump-dem-not): Treat a missing dump file as
	unresolved and report the reason to the log file.

From-SVN: r175224