Ticket #944. Also destory the previous interface if the user changing the vlan tag of an existing vlan entry.
Ticket #944. Also destory the previous interface if the user changing the vlan tag of an existing vlan entry.

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