Fix Nullpointer exception in Saml10ObjectBuilder.newAttributeStatement.

Attention: 
Due to the changes from 4.0 -> 4.1, Saml10SuccessResponseView:93, now
converts all attributes to collections, even if the values are null.
Instead of this, use the loop right below this.

Check if the value is null. If it is, dont add it
If a value in the collection is null, also dont add it

What would a value be null? what circumstances would cause it to be null? 

Also the build is failing.