Remove Puppet configuration for zulip-staging.

The file was already deleted.

(imported from commit 04c68076ad59709c2848f81ca81db9612f9c65b8)

servers/puppet/modules/humbug/manifests/staging_app_frontend.pp

@@ -13,17 +13,4 @@ class humbug::staging_app_frontend {
     ensure => 'link',
     target => '/etc/nginx/sites-available/humbug-staging',
   }
-  file { "/etc/nginx/sites-available/zulip-staging":
-    require => Package[nginx],
-    ensure => file,
-    owner  => "root",
-    group  => "root",
-    mode => 644,
-    source => "puppet:///modules/humbug/nginx/sites-available/zulip-staging",
-  }
-  file { '/etc/nginx/sites-enabled/zulip-staging':
-    ensure => 'link',
-    target => '/etc/nginx/sites-available/zulip-staging',
-  }
-
 }