Delete Items created during Prepared Stat (memory leak bug) (Bug #3451)

sql/sql_parse.cc:
  Delete Items created during Prepared Stat (memory leak bug)
sql/sql_prepare.cc:
  Delete Items created during Prepared Stat (memory leak bug)

sql/sql_parse.cc

@@ -1424,6 +1424,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
   }
   case COM_EXECUTE:
   {
+    thd->free_list= NULL;
     mysql_stmt_execute(thd, packet, packet_length);
     break;
   }

sql/sql_prepare.cc

@@ -1485,9 +1485,7 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
 
   thd->stmt_backup.set_statement(thd);
   thd->set_statement(stmt);
-
   reset_stmt_for_execute(stmt);
-
 #ifndef EMBEDDED_LIBRARY
   if (stmt->param_count)
   {
@@ -1526,6 +1524,11 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
   cleanup_items(stmt->free_list);
   close_thread_tables(thd); // to close derived tables
   thd->set_statement(&thd->stmt_backup);
+  /* 
+    Free Items that were created during this execution of the PS by query
+    optimizer.
+  */
+  free_items(thd->free_list); 
   DBUG_VOID_RETURN;
 
 set_params_data_err: