Fix a crash when refreshing metadata
Fix a crash when refreshing metadata

When processing the file handles it seems g_variant_get() actually wants to
write the fd integer. This bug does not happen every time, and seems to vanish
every time under valgrind.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1460429

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