another user.

When the DEFINER clause isn't specified in the ALTER statement then it's loaded
from the view definition. If the definer differs from the current user then
the error is thrown because only a super-user can set other users as a definers.

Now if the DEFINER clause is omitted in the ALTER VIEW statement then the
definer from the original view is used without check.


mysql-test/t/view_grant.test:
  Added a test case for the bug#27006: The SUPER privilege is wrongly required
  to alter a view created by another user.
mysql-test/r/view_grant.result:
  Added a test case for the bug#27006: The SUPER privilege is wrongly required
  to alter a view created by another user.
sql/sql_view.cc:
  Bug#26813: The SUPER privilege is wrongly required to alter a view created by
  another user.
  Now if the DEFINER clause is omitted in the ALTER VIEW statement then the
  definer from the original view is used without check.