Be more lenient with XMLCacheDir in config
Be more lenient with XMLCacheDir in config

Like this a dev config can still contain it, making it easier to switch
between this and the previous version.

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