Fix some ansible-lint complaints.

cloudbox.yml

@@ -4,12 +4,12 @@
 - name: apply configuration to the cloudbox
   hosts: cloudboxes
   remote_user: ansible
-  become: Yes
+  become: true
   vars:
     if_lan: "enp1s0"
     ipaddr: "192.168.2.50/24"
     gateway: "192.168.2.1"
-    DNS: "192.168.2.1"
+    dns: "192.168.2.1"
     ddns_domain: "something.ddnss.de"
     ddns_updkey: "138638.some.key.here.635620"
     ## 'nc_download' and 'nc_checksum' are only
@@ -32,17 +32,16 @@
 #    - low-power
     - nextcloud
     - nextcloud-upgrade
-    - backup
+#    - backup
 
-
-## Hosts in the the 'only_nextcloud'-group are only upgraded: 
+## Hosts in the the 'only_nextcloud'-group are only upgraded:
 
 - name: upgrade nextcloud only
   hosts: only_nextcloud
   remote_user: ansible
-  become: Yes
+  become: true
   vars:
-    nc_dir: "/var/www/nextcloud" 
+    nc_dir: "/var/www/nextcloud"
     nc_apps:
       - calendar
       - notes
@@ -51,4 +50,3 @@
   roles:
     - up2date-debian
     - nextcloud-upgrade
-