Fix session incompatibility with Memcache and Redis type session storage handlers

An attempt to fix issue 7380 and https://bugs.php.net/bug.php?id=61470, a file-based session issue, causes the following error when using a Memcache or Redis session store w/ Symfony security:  "Authentication exception occurred; redirecting to authentication entry point (A Token was not found in the SecurityContext.)"  Closes 7380.