add convenience 'aptitude update' exec

manifests/os/debian.pp

@@ -55,6 +55,16 @@ class base::os::debian (
     apt_cache_tmp_dir   => $apt_cache_tmp_dir,
   }
 
+  # Define an aptitude update exec that will only get run if it receives a
+  # notification. This is a _convenience_ resource as it will NOT receive a
+  # notification from any resource in _this_ class; it is intended that
+  # _other_ classes notify it.
+  exec { 'aptitude update':
+    command     => 'aptitude update',
+    path        => '/bin:/usr/bin',
+    refreshonly => true,
+  }
+
   # Install basic configuration files.
   file {
     '/etc/default/rcS':