BUG#14593883-REPLICATION BREAKS WHEN SET DATA TYPE

COLUMNS ARE USED INSIDE A STORED PROCEDURE

Post-push fix.
String::operator=() in client/sql_string.h also 
needs to be updated with fix.

client/sql_string.h

 /*
-   Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -228,6 +228,7 @@ public:
       DBUG_ASSERT(!s.uses_buffer_owned_by(this));
       free();
       Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length;
+      str_charset=s.str_charset;
       alloced=0;
     }
     return *this;