Fixed bug #2602 in CACHE INDEX, LOAD INDEX


sql/sql_yacc.yy:
  Fixed bug #2602 in CACHE INDEX, LOAD INDEX
mysql-test/t/key_cache.test:
  Fixed bug #2602 in CACHE INDEX, LOAD INDEX
mysql-test/t/preload.test:
  Fixed bug #2602 in CACHE INDEX, LOAD INDEX
mysql-test/r/key_cache.result:
  Fixed bug #2602 in CACHE INDEX, LOAD INDEX
mysql-test/r/preload.result:
  Fixed bug #2602 in CACHE INDEX, LOAD INDEX