Fix out-of-date comments.

sql/sql_select.cc

@@ -1191,7 +1191,7 @@ JOIN::optimize_inner()
 
   /*
     Needed in case optimizer short-cuts,
-    set properly in make_tmp_tables_info()
+    set properly in make_aggr_tables_info()
   */
   fields= &select_lex->item_list;
 

sql/sql_select.h

@@ -438,7 +438,7 @@ typedef struct st_join_table {
     will be turned to fields. These variables are pointing to
     tmp_fields_list[123]. Valid only for tmp tables and the last non-tmp
     table in the query plan.
-    @see JOIN::make_tmp_tables_info()
+    @see JOIN::make_aggr_tables_info()
   */
   List<Item> *fields;
   /** List of all expressions in the select list */