trivial: Turn off a new GCC8 warning that just triggers false positives
trivial: Turn off a new GCC8 warning that just triggers false positives

vathpela/fwupd,superm1/fwupd,vathpela/fwupd,fwupd/fwupd,superm1/fwupd,hughsie/fwupd,vathpela/fwupd,superm1/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,hughsie/fwupd,fwupd/fwupd,vathpela/fwupd,fwupd/fwupd