CD-1 issue #46: indeterminate attribute assignment expression

The issue number refers to the XLS-sheet found in this email:
http://lists.oasis-open.org/archives/xacml/200909/msg00013.html

The specification is not clear about what happens if an attribute 
assignment expression evaluates to indeterminate.

We must specify this.

I propose that if an attribute assignment expression evaluates to 
indeterminate and the obligation/advice expression to which it belongs 
to has an FullFilOn/AppliesTo which matches the result of the policy 
combining algorithm, then the policy as a whole shall evaluate to 
Indeterminate. If the FullFilOn/AppliesTo does not match the policy 
combining result, then the Indeterminate has no effect.

Best regards,
Erik