Temp stuff on salted-hash for DDT.

@@ -121,10 +121,12 @@
             "wait | continue | panic", "FAILMODE", failuremode_table);
 
         /* hidden properties */
         zprop_register_hidden(ZPOOL_PROP_NAME, "name", PROP_TYPE_STRING,
             PROP_READONLY, ZFS_TYPE_POOL, "NAME");
+        zprop_register_hidden(ZPOOL_PROP_DDT_SALT, "ddt_salt", PROP_TYPE_STRING,
+            PROP_READONLY, ZFS_TYPE_POOL, "DDT_SALT");
 }
 
 /*
  * Given a property name and its type, returns the corresponding property ID.
  */