Prevent sources with zero prefix length being applied every agent run

Author: nabertrand

lib/puppet/provider/firewall/firewall.rb

@@ -325,8 +325,8 @@ def delete(context, name, is)
   def insync?(context, _name, property_name, is_hash, should_hash)
     context.debug("Checking whether '#{property_name}' is out of sync")
 
-    # If either value is nil, no custom logic is required
-    return nil if is_hash[property_name].nil? || should_hash[property_name].nil?
+    # If either value is nil, no custom logic is required unless property is source or destination
+    return nil if (is_hash[property_name].nil? || should_hash[property_name].nil?) && ! [:source, :destination].include?(property_name)
 
     case property_name
     when :protocol