Install socat on zuul executors

This is needed for the intermediate registry jobs.

Change-Id: I98652c4cf4ec0688d18e74d39090bb3b22ad8274

manifests/site.pp

@@ -837,6 +837,14 @@ node /^ze\d+\.open.*\.org$/ {
     ],
   }
 
+  # Socat is also required for pushing/pulling images
+  package { 'socat':
+    ensure  => present,
+    require => [
+      Class['apt::update'],
+    ],
+  }
+
   # NOTE(pabelanger): We call ::zuul directly, so we can override all in one
   # settings.
   class { '::zuul':