fix idempotency on mergerfs role

roles/mergerfs/tasks/disks.yml

@@ -5,7 +5,6 @@
     state: directory
     owner: "{{ item.owner | default('root') }}"
     group: "{{ item.group | default('root') }}"
-    mode: "{{ item.mode | default('0750') }}"
   with_items:
     - "{{ mergerfs_disks }}"
     - "{{ mergerfs_fstab }}"