Fix check for removing etcd member (#5051)

Change-Id: Ib27d051ff111f813097a9b33a86465a2a30a6db0

roles/remove-node/post-remove/tasks/main.yml

@@ -51,4 +51,4 @@
   delegate_to: "{{ groups['etcd']|first }}"
   when:
     - inventory_hostname in groups['etcd']
-    - not etcd_member_id.stdout
+    - etcd_member_id.stdout | length > 0