sigrok-native-appimage: Add bugfix patch for AppImageKit.

sigrok-native-appimage: Add bugfix patch for AppImageKit.

The problem was that relative paths would not work, since AppRun
(part of the AppImage) would chdir() into the AppImage mount point
(/tmp/.mount_xxxxx/usr), which would make glib's g_get_current_dir() return
that path, so all glib functions calling that would do the wrong thing.

For now, we fix this by patching away the chdir() in AppRun.

Details:
https://github.com/AppImage/AppImageKit/issues/172#issuecomment-229993161

This fixes bug #1300.