Fix idempotency problem when getting rid of S3 setup

roles/matrix-server/tasks/setup_s3fs.yml

@@ -25,16 +25,21 @@
 #
 # Tasks related to getting rid of s3fs (if it was previously enabled)
 #
+
+- name: Check existance of matrix-s3fs service
+  stat: path="/etc/systemd/system/matrix-s3fs.service"
+  register: matrix_s3fs_service_stat
+
 - name: Ensure matrix-s3fs is stopped
   service: name=matrix-s3fs state=stopped daemon_reload=yes
   register: stopping_result
-  when: "not matrix_s3_media_store_enabled"
+  when: "not matrix_s3_media_store_enabled and matrix_s3fs_service_stat.stat.exists"
 
 - name: Ensure matrix-s3fs.service doesn't exist
   file:
-    path: "{{ matrix_base_data_path }}/s3fs-credentials"
+    path: "/etc/systemd/system/matrix-s3fs.service"
     state: absent
-  when: "not matrix_s3_media_store_enabled"
+  when: "not matrix_s3_media_store_enabled and matrix_s3fs_service_stat.stat.exists"
 
 - name: Ensure s3fs-credentials doesn't exist
   file: