Fixed problem in access rights testing (from last patch)


mysql-test/r/group_by.result:
  Condenced GROUP test case
mysql-test/t/group_by.test:
  Condenced GROUP test case
sql/sql_parse.cc:
  Fixed problem in access rights testing (from last patch)
sql/sql_select.cc:
  Rollback Sinisa's GROUP BY patch and make a better one.