Supplied the default database name for ALTER TABLE ... RENAME 
for the new table instead of the old tables db like we do for 
other ALTERs.


mysql-test/r/alter_table.result:
  Bug#11493 - Alter table rename to default database does not work without db name qualifying
  The test result.
mysql-test/t/alter_table.test:
  Bug#11493 - Alter table rename to default database does not work without db name qualifying
  The test case.