fix inverted back and front ports...(media relay)
fix inverted back and front ports...(media relay)

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