Replace injected Ansible fact variables in etcd role (#13338)

roles/etcd_defaults/defaults/main.yml

@@ -49,7 +49,7 @@ etcd_extra_vars: {}
 ## Etcd is restricted by default to 512M on systems under 4GB RAM, 512MB is not enough for much more than testing.
 ## Set this if your etcd nodes have less than 4GB but you want more RAM for etcd. Set to 0 for unrestricted RAM.
 ## This value is only relevant when deploying etcd with `etcd_deployment_type: docker`
-etcd_memory_limit: "{% if ansible_memtotal_mb < 4096 %}512M{% else %}0{% endif %}"
+etcd_memory_limit: "{% if ansible_facts['memtotal_mb'] < 4096 %}512M{% else %}0{% endif %}"
 
 ## Etcd has a default of 2G for its space quota. If you put a value in etcd_memory_limit which is less than
 ## etcd_quota_backend_bytes, you may encounter out of memory terminations of the etcd cluster. Please check