It's dead code when CONFIG_SPICE is off.  If it wasn't, it would crash
dereferencing the null pointer returned by the qmp_query_spice()
dummy in qmp.c.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NGerd Hoffmann <kraxel@redhat.com>