A post-merge fix.

sql/sql_parse.cc:
  A post-merge fix (broken alter_table.test): restore Svoj's fix
  for Bug#23404 lost during merge.

sql/sql_parse.cc

@@ -2641,6 +2641,7 @@ unsent_create_error:
 
     bzero((char*) &create_info, sizeof(create_info));
     create_info.db_type= DB_TYPE_DEFAULT;
+    create_info.row_type= ROW_TYPE_NOT_USED;
     create_info.default_table_charset= thd->variables.collation_database;
 
     res= mysql_alter_table(thd, tables->db, tables->real_name,