Revert "turn preferences into a simple file"

This reverts commit 0011e70a24.

manifests/init.pp

@@ -44,7 +44,7 @@ class apt {
 	config_file {
 		# this just pins unstable and testing to very low values
 		"/etc/apt/preferences":
-			source => "puppet://$servername/apt/preferences",
+			content => template("apt/preferences.erb"),
 			# use File[apt_config] to reference a completed configuration
 			# See "The Puppet Semaphor" 2007-06-25 on the puppet-users ML
 			alias => apt_config,