Really remove Ubuntu Cloud Archive for now

* modules/jenkins/manifests/slave.pp: Make sure the sources.list.d
file for UCA left behind by the revert of bdcc115 gets cleaned up so
we don't accidentally install new packages from it.

Change-Id: Icf3243b08f0ab3904b29031857db01f735d0f410

modules/jenkins/manifests/slave.pp

@@ -71,6 +71,10 @@ class jenkins::slave(
     $packages = $common_packages
   }
 
+  file { '/etc/apt/sources.list.d/cloudarchive.list':
+    ensure => absent,
+  }
+
   package { $packages:
     ensure => present,
   }