cleaner local facts filter

Just a trivial refactor that I forgot to do before submitting #240

Author: binford2k

lib/puppet/node/facts.rb

@@ -29,10 +29,12 @@ def save(instance, key = nil, options = {})
 
   def add_local_facts(query = [])
     query = Array(query) # some use cases result in a nil being passed in
-    values["implementation"] = Puppet.implementation if query.empty? or query.include? 'implementation'
-    values["clientcert"] = Puppet.settings[:certname] if query.empty? or query.include? 'clientcert'
-    values["clientversion"] = Puppet.version.to_s if query.empty? or query.include? 'clientversion'
-    values["clientnoop"] = Puppet.settings[:noop] if query.empty? or query.include? 'clientnoop'
+    return if query.empty?
+
+    values["implementation"] = Puppet.implementation if query.include? 'implementation'
+    values["clientcert"] = Puppet.settings[:certname] if query.include? 'clientcert'
+    values["clientversion"] = Puppet.version.to_s if query.include? 'clientversion'
+    values["clientnoop"] = Puppet.settings[:noop] if query.include? 'clientnoop'
   end
 
   def initialize(name, values = {})