etcd.conf.yml.sample: remove deprecated fields

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

etcd.conf.yml.sample

@@ -94,9 +94,6 @@ proxy-write-timeout: 5000
 proxy-read-timeout: 0
 
 client-transport-security:
-  # DEPRECATED: Path to the client server TLS CA file.
-  ca-file:
-
   # Path to the client server TLS cert file.
   cert-file:
 
@@ -113,9 +110,6 @@ client-transport-security:
   auto-tls: false
 
 peer-transport-security:
-  # DEPRECATED: Path to the peer server TLS CA file.
-  ca-file:
-
   # Path to the peer server TLS cert file.
   cert-file:
 
@@ -142,3 +136,6 @@ log-output: [default]
 
 # Force to create a new one member cluster.
 force-new-cluster: false
+
+auto-compaction-mode: periodic
+auto-compaction-retention: "1"