plugins types REFACTOR remove hash callback

... and use LYB value instead, there is no good reason
for the hash key and LYB value to differ.
diff --git a/src/validation.c b/src/validation.c
index b7f5abb..8a05adc 100644
--- a/src/validation.c
+++ b/src/validation.c
@@ -1106,7 +1106,7 @@
                     }
 
                     /* get hash key */
-                    hash_key = val->realtype->plugin->hash(val, &dyn, &key_len);
+                    hash_key = val->realtype->plugin->print(NULL, val, LY_VALUE_LYB, NULL, &dyn, &key_len);
                     hash = dict_hash_multi(hash, hash_key, key_len);
                     if (dyn) {
                         free((void *)hash_key);