CORE-1402: implemented a servlet to inform users that the logout was successful as well as a logout success handler implementation to use with our CAS-secured web applications
(cherry picked from commit 3596d76fa4c33748553dd19b6c72b2ccab5bd0cf)
CORE-1402: changed the level of a log statement
(cherry picked from commit 0ef70758800fb7ce012aa093a4c0425b85dbc0c3)