Fixed that GROUP BY can take DESC


Docs/manual.texi:
  Cleanups
client/mysqltest.c:
  Added --replace to mysqltest
mysql-test/t/backup.test:
  Fix to handle different error codes from backup table
sql-bench/crash-me.sh:
  Fixed error in create_index test
sql/item_func.cc:
  Cleanup
sql/sql_yacc.yy:
  Fixed that GROUP BY can take DESC