[FIX] PDF conversion of files attached to categ
[FIX] PDF conversion of files attached to categ

- closes #1279

mvidalgarcia/indico,DirkHoffmann/indico,indico/indico,OmeGak/indico,mvidalgarcia/indico,DirkHoffmann/indico,pferreir/indico,ThiefMaster/indico,pferreir/indico,mvidalgarcia/indico,ThiefMaster/indico,indico/indico,mic4ael/indico,ThiefMaster/indico,OmeGak/indico,pferreir/indico,ThiefMaster/indico,mic4ael/indico,mvidalgarcia/indico,mic4ael/indico,DirkHoffmann/indico,indico/indico,OmeGak/indico,DirkHoffmann/indico,OmeGak/indico,indico/indico,mic4ael/indico,pferreir/indico