Merge bk-internal.mysql.com:/data0/bk/mysql-5.0-opt

into  bk-internal.mysql.com:/data0/bk/mysql-5.1-opt


mysql-test/r/query_cache.result:
  Auto merged
mysql-test/t/query_cache.test:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_cache.cc:
  Auto merged