This fix optionally reverts CAS-1065. See CAS-1166 and CAS-1168.
Cleaned up my comment, added JavaDoc to the new method.
Merge pull request #321 from Unicon/CAS-1166

CAS-1166/1168 (3.5.x) login form is not shown on error of Spnego/login form is not shown on error of Spnego