There was a wrong determination of the DB name (witch is 
not always the one in TABLE_LIST because derived tables
may be calculated using temp tables that have their db name
set to "").
The fix determines the database name according to the type 
of table reference, and calls the function check_access() 
with the correct db name so the correct set of grants is found.


mysql-test/r/view_grant.result:
  testsuite for the bug
mysql-test/t/view_grant.test:
  testsuite for the bug
sql/sql_parse.cc:
  correct determination of the db name.