#32 BasicEvaluationCtx does a lookup even when an AttributeVa...

[Roland Illig]

Subject: BasicEvaluationCtx does a lookup even when an AttributeValue is given in the RequestCtx

To fix it, I added the following code at the very beginning of getSubjectAttribute:

if (category == null) category = Subject.DEFAULT_CATEGORY;

Then, suddenly, everything worked as expected.