puppet: Tidy old golang directories.

This relies on behavior which is only in Puppet 5.5.1 and above, which
means it must be skipped on Ubuntu 18.04.

puppet/zulip/manifests/golang.pp

@@ -18,4 +18,23 @@ class zulip::golang {
     ensure  => file,
     require => Zulip::Sha256_tarball_to['golang'],
   }
+
+  file { $dir:
+    ensure  => directory,
+    require => Zulip::Sha256_tarball_to['golang'],
+  }
+
+  unless $::operatingsystem == 'Ubuntu' and $::operatingsystemrelease == '18.04' {
+    # Puppet 5.5.0 and below make this always-noisy, as they spout out
+    # a notify line about tidying the managed directory above.  Skip
+    # on Bionic, which has that old version; they'll get tidied upon
+    # upgrade to 20.04.
+    tidy { '/srv/zulip-golang-*':
+      path    => '/srv/',
+      recurse => 1,
+      rmdirs  => true,
+      matches => 'zulip-golang-*',
+      require => File[$dir],
+    }
+  }
 }