[FIX] GenericCache{file} race condition
[FIX] GenericCache{file} race condition

- don't create folders when READING. it makes zero sense.
- don't fail because of a race condition when creating the folders

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