Flatpak relies on OSTree to report the progress, and
OSTree's progress report frequency fallbacks to 1 second.
Recently, however, OSTree received support for setting
custom update frequencies. Since it relies on GVariant
options, if the user has an older OSTree, it'll simply
be ignored.
This patch, then, makes Flatpak report progress every
100ms rather than the default value of 1 second.
flatpak/flatpak#609