force travis to use newer gcc.
force travis to use newer gcc.

secureosv/pythia,rusthon/Rusthon,kustomzone/Rusthon,rootfs/Rusthon,tempbottle/Rusthon,pombredanne/Rusthon,tempbottle/Rusthon,pombredanne/Rusthon,kustomzone/Rusthon,secureosv/pythia,rootfs/Rusthon,rootfs/Rusthon,kustomzone/Rusthon,rootfs/Rusthon,tempbottle/Rusthon,pombredanne/Rusthon,pombredanne/Rusthon,kustomzone/Rusthon,rootfs/Rusthon,tempbottle/Rusthon,kustomzone/Rusthon,rusthon/Rusthon,secureosv/pythia,secureosv/pythia,rusthon/Rusthon,rusthon/Rusthon,pombredanne/Rusthon,secureosv/pythia,rusthon/Rusthon,tempbottle/Rusthon