Add workaround to flatpak_repo_collect_sizes for uncommited objects
Add workaround to flatpak_repo_collect_sizes for uncommited objects

It turns out the underlying call ostree_repo_query_object_storage_size
doesn't work for staged objects, so we work around this by actually
loading the object, walking back to the original unix input stream
and fstat:ing the fd from that.

flatpak/flatpak,matthiasclasen/flatpak,handsome-feng/flatpak,handsome-feng/flatpak,GeorgesStavracas/flatpak,handsome-feng/flatpak,GeorgesStavracas/flatpak,flatpak/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,flatpak/flatpak,GeorgesStavracas/flatpak,GeorgesStavracas/flatpak,flatpak/flatpak,flatpak/flatpak,matthiasclasen/flatpak,GeorgesStavracas/flatpak,handsome-feng/flatpak,handsome-feng/flatpak