Add --old-redirects-only option to maintenance/refreshLinks.php, to add old redirects...

Add --old-redirects-only option to maintenance/refreshLinks.php, to add old redirects to the redirect table.  This may be worth trying out on at least some of the smaller wikis.  It seems to work correctly, and pretty quickly for a couple thousand redirects to fix, although truncating the redirect table and running it inevitably gives a different number (probably due to incorrect redirect table entries to start with).  With the limit options, it might be tried on bigger wikis too.