Fix error reported in https://forum.pfsense.org/index.php?topic=105078.0
Fix error reported in https://forum.pfsense.org/index.php?topic=105078.0

Fix select name, [] is always added when multiple is set to true

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