flatpak enter: Stop parsing context options
flatpak enter: Stop parsing context options

We don't make any use of these options, and the documentation
does not mention them either, so stop accepting them.

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