Do not set user on nginx cache volume

When volumemgr role runs, the 'nginx' user may not exist yet.
We set the correct permissions in the Ansible role instead.

services.yml.default

@@ -18,9 +18,6 @@ frontend:
   volumes:
     - name: cache
       path: /var/cache/nginx
-      owner: nginx
-      group: nginx
-      mode: "0700"
       size: 20g
 
 reports-collector:

services.yml.no-elasticsearch

@@ -18,9 +18,6 @@ frontend:
   volumes:
     - name: cache
       path: /var/cache/nginx
-      owner: nginx
-      group: nginx
-      mode: "0700"
       size: 20g
 
 log-collector: