DATABASE SECURITY

The problem was that CREATE PROCEDURE/FUCTION could be used to
check the existence of databases for which the user had no
privileges and therefore should not be allowed to see.

The reason was that existence of a given database was checked
before privileges. So trying to create a stored routine in
a non-existent database would give a different error than trying
to create a stored routine in a restricted database.

This patch fixes the problem by changing the order of the checks
for CREATE PROCEDURE/FUNCTION so that privileges are checked first.
This means that trying to create a stored routine in a
non-existent database and in a restricted database both will
give ER_DBACCESS_DENIED_ERROR error.

Test case added to grant.test.