bring back subnetv4_expand function used by pfblockerng
bring back subnetv4_expand function used by pfblockerng

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