--- sql/sql_acl.cc	2016-03-03 16:35:33.000000000 +0100
+++ sql/sql_acl.cc	2017-05-09 11:28:16.879062433 +0200
@@ -3029,7 +3029,7 @@
       * An empty password is considered to be of mysql_native type.
     */
     
-    if (combo->plugin.str == NULL || combo->plugin.str == '\0')
+    if (combo->plugin.str == NULL)
     {
       if (combo->uses_identified_by_password_clause)
       {