block/raw: Fix to forward method bdrv_media_changed()
Block driver "raw" forwards most methods to the underlying block
driver. However, it doesn't implement method bdrv_media_changed().
Makes bdrv_media_changed() always return -ENOTSUP.
I believe -fda /dev/fd0 gives you raw over host_floppy, and disk
change detection (fdc register 7 bit 7) is broken. Testing my theory
requires a computer museum, though.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>