fix error running post update commands

Fixes this error:

Error: /Stage[main]/Nextcloud::Update/Exec[post-update command]: Could not evaluate: Working directory /opt/nextcloud-24.0.7/nextcloud does not exist!

This error would only occur when $update_host is set and the update
was not completed yet.

manifests/update.pp

@@ -54,7 +54,7 @@
     exec { 'post-update command':
       command   => $nextcloud::post_update_cmd,
       path      => $nextcloud::path,
-      cwd       => $nextcloud::distribution_dir,
+      cwd       => $nextcloud::symlink,
       onlyif    => $post_update_onlyif,
       logoutput => $nextcloud::debug,
     }