Include the protocol in the proxy URL

The current proxy_client template makes it possible to communicate with
the proxy only via HTTP. Add the protocol to the variable so that it's
possible to change the protocol.

Signed-off-by: Gabriel Filion <lelutin@gmail.com>

manifests/proxy_client.pp

@@ -1,7 +1,7 @@
 class apt::proxy_client {
 
   $real_apt_proxy = $apt_proxy ? {
-    "" => "localhost",
+    "" => "http://localhost",
     default => $apt_proxy
   }
 

templates/20proxy.erb

@@ -1,4 +1,4 @@
 # This file is brought to you by Puppet
 # all local modifications will be overwritten
 
-Acquire::http { Proxy "http://<%= real_apt_proxy %>:<%= real_apt_proxy_port %>"; };
+Acquire::http { Proxy "<%= real_apt_proxy %>:<%= real_apt_proxy_port %>"; };