illumos gate

The add_config function in libzfs fails to free the passed in config nvlist in a couple of cases. If the following condition is true, the config will be leaked:

        if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE,
            &state) == 0 &&
            (state == POOL_STATE_SPARE || state == POOL_STATE_L2CACHE) &&
            nvlist_lookup_uint64(config, ZPOOL_CONFIG_GUID, &vdev_guid) == 0) {

All other paths though this function free the config - regardless of whether the function succeeded. Since the caller and the rest of this function assumes that add_config frees the passed in config, it makes sense to fix the 3 cases places in this if statement that leak it.