Silence useless facter errors when calling crm_node

When calling crm_node -n we can drop stderr so that people
are not confused about the following error:

$ crm_node -n
error: Could not connect to cluster (is it running?)
$ crm_node -n 2>/dev/null
$

Change-Id: Ie774ff5862cf5f28f712e009d271055eb5d646d0

lib/facter/pacemaker_node_name.rb

@@ -4,7 +4,7 @@ require 'facter'
 if not File.exists?('/.dockerenv') and not File.exists?('/run/.containerenv')
   Facter.add('pacemaker_node_name') do
     setcode do
-      Facter::Core::Execution.exec 'crm_node -n'
+      Facter::Core::Execution.exec 'crm_node -n 2>/dev/null'
     end
   end
 end