Don't panic on unencrypted block in encrypted dataset

While 763ca47 closes the situation of block cloning creating
unencrypted records in encrypted datasets, existing data still causes
panic on read. Setting zfs_recover bypasses this but at the cost of
potentially ignoring more serious issues.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Peredun <chris.peredun@ixsystems.com>
Closes openzfs#15677

module/zfs/dbuf.c

@@ -1619,8 +1619,6 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags,
 	 */
 	if (db->db_objset->os_encrypted && !BP_USES_CRYPT(bpp)) {
 		spa_log_error(db->db_objset->os_spa, &zb, &bpp->blk_birth);
-		zfs_panic_recover("unencrypted block in encrypted "
-		    "object set %llu", dmu_objset_id(db->db_objset));
 		err = SET_ERROR(EIO);
 		goto early_unlock;
 	}

module/zfs/dmu_send.c

@@ -1124,8 +1124,6 @@ send_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 	if (sta->os->os_encrypted &&
 	    !BP_IS_HOLE(bp) && !BP_USES_CRYPT(bp)) {
 		spa_log_error(spa, zb, &bp->blk_birth);
-		zfs_panic_recover("unencrypted block in encrypted "
-		    "object set %llu", dmu_objset_id(sta->os));
 		return (SET_ERROR(EIO));
 	}