NH-2664 Linq, cannot query dynamic-component

Not much to say really. Maybe the place for the change feels a bit strange, but making the IHqlGeneratorForMethod support it would have required a more breaking change.

https://nhibernate.jira.com/browse/NH-2664
I copied your code and customize by myself, but it looks unuseable.
DynamicTestModel is like Product
roles = (from p in session.QueryOver<DynamicTestModel>() 
             where p.CustomProperties[columnName] == "abc" 
             select p).List();

When I debug into NHibernate.Criterion.CriterionUtil line 76, I saw criteria value is "CustomProperties = abc", but the right result might be "Name = abc", propertyName is "CustomProperties". Then throw a QueryException, "message is Type mismatch in NHibernate.Criterion.SimpleExpression: CustomProperties expected type System.Collections.IDictionary, actual type System.String"