Use different value_instance lookup for xml parsing.
Use different value_instance lookup for xml parsing.

There are two usages for the value_instance_by_selector function.
One is used during evaluation, another one during xml parsing.
The former one needs to take trac#142 requirement into account,
while the latter must not.

redhatrises/openscap,postfix/openscap,redhatrises/openscap,ybznek/openscap,redhatrises/openscap,openprivacy/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,isimluk/openscap,openprivacy/openscap,mpreisler/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,redhatrises/openscap,redhatrises/openscap,mpreisler/openscap,ybznek/openscap,OpenSCAP/openscap,jan-cerny/openscap,ybznek/openscap,ybznek/openscap,ybznek/openscap,isimluk/openscap,mpreisler/openscap,mpreisler/openscap,postfix/openscap,OpenSCAP/openscap,Hexadorsimal/openscap,jan-cerny/openscap,openprivacy/openscap,OpenSCAP/openscap,redhatrises/openscap,isimluk/openscap,jan-cerny/openscap,mpreisler/openscap,OpenSCAP/openscap,isimluk/openscap,openprivacy/openscap,mpreisler/openscap,jan-cerny/openscap,OpenSCAP/openscap,jan-cerny/openscap,Hexadorsimal/openscap,openprivacy/openscap,isimluk/openscap,postfix/openscap,isimluk/openscap,OpenSCAP/openscap,jan-cerny/openscap,postfix/openscap,postfix/openscap,ybznek/openscap,openprivacy/openscap,postfix/openscap