validate dropdowns for security reasons
validate dropdowns for security reasons

*really* fixes #2494 :-)

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