UP-4192 CVE-2014-5059 guarantee CAS security context successfully sets principal ID.

Detects and throws in case where principal UID setting is blocked.
UP-4192 CVE-2014-5059 block security vulnerability.

Fixes out of the box `security.properties` configuration.
Adds warning to `security.properties` documenting the configuration trap.

Conflicts:
	uportal-war/src/main/resources/properties/security.properties
UP-4192 CVE-2014-5059 Restore SSP CAS disablement

Previous UP-4192 patch to security.properties was integrated into
SSP source mostly as-is with just a few fix-ups for Git conflicts
so we have a reasonable baseline against which to track
truly SSP-specific customizations, of which this commit is one.

In particular it re-disabled the CAS security context. It also
fixes a minor typo in a comment.