Use strings in whitelist to avoid mismatch of object_id

Author: krismichalski

lib/jsonapi/configuration.rb

@@ -183,7 +183,7 @@ def route_formatter
     end
 
     def exception_class_whitelisted?(e)
-      @exception_class_whitelist.flatten.any? { |k| e.class.ancestors.include?(k) }
+      @exception_class_whitelist.flatten.any? { |k| e.class.ancestors.map(&:to_s).include?(k.to_s) }
     end
 
     def default_processor_klass=(default_processor_klass)