COLUMNS ARE USED INSIDE A STORED PROCEDURE                                      
                                                                                
Problem: The operator '=' overload method inside
'String' class is not coping str_charset member from
R.H.S object to L.H.S object. Hence charset is wrongly
set while using string assignments

Analaysis: The above mentioned problem is
identified while doing the analaysis of bug#14593883.
Though the test scenario mentioned in the bug page
is not  an issue in mysql-5.1 code, the actual root cause
ie., "str_charset member is not copied" exists in the 
mysql-5.1 code base. 

Fix: Handle coping str_charset member in operator '=' overload                  
method.