Added flag to detect renaming of fields (not supported as fast alter table for...

Added flag to detect renaming of fields (not supported as fast alter table for ndbcluster): psot review comment: cleared flag before checking

sql/sql_table.cc

@@ -4745,10 +4745,12 @@ static uint compare_tables(TABLE *table, List<create_field> *create_list,
       create_info->table_options|= HA_OPTION_PACK_RECORD;
 
     /* Check if field was renamed */
+    field->flags&= ~FIELD_IS_RENAMED;
     if (my_strcasecmp(system_charset_info,
 		      field->field_name,
 		      new_field->field_name))
       field->flags|= FIELD_IS_RENAMED;      
+
     /* Evaluate changes bitmap and send to check_if_incompatible_data() */
     if (!(tmp= field->is_equal(new_field)))
       DBUG_RETURN(ALTER_TABLE_DATA_CHANGED);