trivial: Fix a tiny memory leak when setting the summary
trivial: Fix a tiny memory leak when setting the summary

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