Convert ASSERT() to VERIFY() for better coverage

module/zfs/vdev_disk.c

@@ -468,8 +468,7 @@ vdev_disk_io_done(zio_t *zio)
 	 * asynchronous removal of the device. Otherwise, probe the device and
 	 * make sure it's still accessible.
 	 */
-	if (zio->io_error == EIO) {
-		ASSERT(0); /* XXX: Not yet supported */
+	VERIFY3S(zio->io_error, ==, 0);
 #if 0
 		vdev_t *vd = zio->io_vd;
 		vdev_disk_t *dvd = vd->vdev_tsd;
@@ -482,7 +481,6 @@ vdev_disk_io_done(zio_t *zio)
 		}
 #endif
 }
-}
 
 vdev_ops_t vdev_disk_ops = {
 	vdev_disk_open,