the fix for 'columns' table only
    Rights check for 'routines' table is already done
    (see WL2131 Access control for SHOW ... PROCEDURE|FUNCTION ...)
    rename 'testtets' database to 'mysqltest' to keep number of
      DBs which created by mysql-test as small as possible


mysql-test/r/information_schema.result:
  Fix for bug#7214: information_schema: unauthorized user can see metadata
mysql-test/t/information_schema.test:
  Fix for bug#7214: information_schema: unauthorized user can see metadata
sql/sql_show.cc:
  Fix for bug#7214: information_schema: unauthorized user can see metadata