Issue 4663 - Remove ~rsync/.ssh/known_hosts resource and update download source

modules/downloadserver/manifests/init.pp

 class downloadserver(
     $domain,
     $certificate,
     $private_key,
     $is_default = false
   ) {
 
   class {'nginx':
     worker_connections => 4000,
     ssl_session_cache => off,
@@ skipping 80 matching lines @@
     managehome => true
   }
 
   file {'/home/rsync/.ssh':
     ensure => directory,
     require => User['rsync'],
     owner => rsync,
     mode => 0600;
   }
 
-  file {'/home/rsync/.ssh/known_hosts':
-    ensure => file,
-    owner => rsync,
-    mode => 0444,
-    source => 'puppet:///modules/downloadserver/known_hosts'
-  }
-
   file {'/home/rsync/.ssh/id_rsa':
     ensure => file,
     owner => rsync,
     mode => 0400,
     source => 'puppet:///modules/private/rsync@downloads.adblockplus.org'
   }
 
   file {'/home/rsync/.ssh/id_rsa.pub':
     ensure => file,
     owner => rsync,
     mode => 0400,
     source => 'puppet:///modules/private/rsync@downloads.adblockplus.org.pub'
   }
 
   cron {'mirror-devbuilds':
     ensure => present,
-    require => [File['/home/rsync/.ssh/known_hosts'],
-                File['/home/rsync/.ssh/id_rsa'],
-                File['/var/www/devbuilds']],
-    command => 'rsync -e ssh -ltprz --delete devbuilds@ssh.adblockplus.org:. /var/www/devbuilds',
+    require => [
+      File['/home/rsync/.ssh/id_rsa'],
+      File['/var/www/devbuilds'],
+    ],
+    command => 'rsync -e ssh -ltprz --delete devbuilds@server16.adblockplus.org:. /var/www/devbuilds',
     environment => hiera('cron::environment', []),
     user => rsync,
     hour => '*',
     minute => '4-54/10'
   }
 }