[CCR] Removed unused static parse field.

Author: martijnvg

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ccr/action/PutAutoFollowPatternAction.java

@@ -42,8 +42,6 @@ public AcknowledgedResponse newResponse() {
 
     public static class Request extends AcknowledgedRequest<Request> implements ToXContentObject {
 
-        static final ParseField LEADER_CLUSTER_FIELD = new ParseField("leader_cluster");
-
         private static final ObjectParser<Request, String> PARSER = new ObjectParser<>("put_auto_follow_pattern_request", Request::new);
 
         private static final ParseField NAME_FIELD = new ParseField("name");