unifying: Fix a compile warning with the latest GLib
unifying: Fix a compile warning with the latest GLib

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