virtio-devices: Rename BlockIoUring to Block

Now that BlockIoUring is the only implementation of virtio-block,
handling both synchronous and asynchronous backends based on the
AsyncIo trait, we can rename it to Block.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/device_manager.rs

@@ -1670,7 +1670,7 @@ impl DeviceManager {
             };
 
             let dev = Arc::new(Mutex::new(
-                virtio_devices::BlockIoUring::new(
+                virtio_devices::Block::new(
                     id.clone(),
                     image,
                     disk_cfg