Remove special characters from interface descriptions during m0n0wall upgrade.
Remove special characters from interface descriptions during m0n0wall upgrade.

Also unset the config.cache if it exists.

BlackstarGroup/pfsense,phil-davis/pfsense,pfsense/pfsense,ptorsten/pfsense,dennypage/pfsense,ch1c4um/pfsense,brunostein/pfsense,ptorsten/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,BlackstarGroup/pfsense,NOYB/pfsense,jxmx/pfsense,ch1c4um/pfsense,NewEraCracker/pfsense,dennypage/pfsense,ch1c4um/pfsense,phil-davis/pfsense,phil-davis/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,ch1c4um/pfsense,jxmx/pfsense,brunostein/pfsense,pfsense/pfsense,NewEraCracker/pfsense,NewEraCracker/pfsense,pfsense/pfsense,jxmx/pfsense,pfsense/pfsense,NOYB/pfsense,NewEraCracker/pfsense,phil-davis/pfsense,brunostein/pfsense,NOYB/pfsense,ptorsten/pfsense