Re-fix 'except' not being honored when used with 'comment_required'

- collectiveidea#418

lib/audited/auditor.rb

@@ -251,15 +251,22 @@ def write_audit(attrs)
       end
 
       def presence_of_audit_comment
-        if comment_required_state?
-          errors.add(:audit_comment, "Comment can't be blank!") unless audit_comment.present?
+        unless commenting_requirements_met?
+          errors.add(:audit_comment, "Comment can't be blank!")
         end
       end
 
-      def comment_required_state?
-        auditing_enabled &&
-          ((audited_options[:on].include?(:create) && self.new_record?) ||
-          (audited_options[:on].include?(:update) && self.persisted? && self.changed?))
+      def commenting_requirements_met?
+        if !auditing_enabled ||
+          audit_comment.present? ||
+          (audited_options[:on].exclude?(:create) && self.new_record?) ||
+          (audited_options[:on].exclude?(:update) && self.persisted?) ||
+          (audited_changes.empty? && self.persisted?)
+        then
+          false
+        else
+          true
+        end
       end
 
       def combine_audits_if_needed