Replaced NULL by nullptr for unique_ptr
Replaced NULL by nullptr for unique_ptr

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