fix crash when no ipv6
fix crash when no ipv6

gale320/flexisip,BelledonneCommunications/flexisip,biddyweb/flexisip,biddyweb/flexisip,BelledonneCommunications/flexisip,BelledonneCommunications/flexisip,gale320/flexisip,gale320/flexisip,biddyweb/flexisip,biddyweb/flexisip,BelledonneCommunications/flexisip,gale320/flexisip