Add package definition for python-software-properties

manifests/ppa.pp

@@ -5,6 +5,8 @@ define apt::ppa(
 ) {
 	include apt
 
+    package { "python-software-properties": }
+
 	exec { "/usr/bin/add-apt-repository ${name}":
 		require => Package["python-software-properties"],
 		# TODO: unless => 'check'