blockdev: Print a warning for legacy drive options that belong to -device

We likely do not want to carry these legacy -drive options along forever.
Let's emit a deprecation warning for the -drive options that have a
replacement with the -device option, so that the (hopefully few) remaining
users are aware of this and can adapt their scripts / behaviour accordingly.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>