Minor nits in cleanfeed install

[Julien-Elie]

I've followed http://www.mixmin.net/cleanfeed/install.html and I have 2 remarks:

• there are more bad_* files to download in cleanfeed/etc

• when doing the perl -wc check, I get a warning. Not important, but as the documentation says there shouldn't be any warning, I believe it should be fixed:

~/bin/filter% perl -wc filter_innd.pl
Name "main::lines" used only once: possible typo at filter_innd.pl line 588.