Don't try to extract libgsystem.so as it is no longer needed
gnome-desktop-testing stopped bundling libgsystem and since version 2018.1-1 it does not need it at all.
We ship gnome-desktop-testing 2018.1-2 from Debian Buster, so drop the entry.
gnome-desktop-testing stopped bundling libgsystem and since version 2018.1-1 it does not need it at all.
We ship gnome-desktop-testing 2018.1-2 from Debian Buster, so drop the entry.