Create dnsmasq-tftp-server.conf at the correct timing

It should be created during the config phase, especially after
the packages are installed.

Change-Id: I3868a0d2ffa5c71077df091918d9d46d83543992

manifests/pxe.pp

@@ -223,6 +223,8 @@ class ironic::pxe (
       owner   => 'root',
       group   => 'root',
       content => template('ironic/dnsmasq_tftp_server.erb'),
+      require => Anchor['ironic::config::begin'],
+      before  => Anchor['ironic::config::end'],
     }
 
     if $manage_service {