illumos gate

When removing a cache device, we reload the cache device list, dropping
the now unused devices. From spa_load_l2cache():

1221     /*
   1222      * Purge vdevs that were dropped
   1223      */
   1224     for (i = 0; i < oldnvdevs; i++) {
   1225         uint64_t pool;
   1226 
   1227         vd = oldvdevs[i];
   1228         if (vd != NULL) {
   1229             if (spa_l2cache_exists(vd->vdev_guid, &pool) &&
   1230                 pool != 0ULL && l2arc_vdev_present(vd))
   1231                 l2arc_remove_vdev(vd);
   1232             (void) vdev_close(vd);
   1233             spa_l2cache_remove(vd);
   1234         }
   1235     }

We don't free the vdev here causing a leak, with accompanying
leaks of vdev_path, vdev_physpath and vdev_devid.