changed persistent task name to be of similar structure as the others

Author: martijnvg

x-pack/plugin/ccr/qa/multi-cluster-with-security/src/test/java/org/elasticsearch/xpack/ccr/FollowIndexSecurityIT.java

@@ -125,7 +125,7 @@ private int countCcrNodeTasks() throws IOException {
         for (Map.Entry<?, ?> entry : nodeTasks.entrySet()) {
             Map<?, ?> nodeTask = (Map<?, ?>) entry.getValue();
             String action = (String) nodeTask.get("action");
-            if (action.startsWith("shard_follow")) {
+            if (action.startsWith("xpack/ccr/shard_follow_task")) {
                 numNodeTasks++;
             }
         }

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

@@ -25,7 +25,7 @@
 
 public class ShardFollowTask implements PersistentTaskParams {
 
-    public static final String NAME = "shard_follow";
+    public static final String NAME = "xpack/ccr/shard_follow_task";
 
     // list of headers that will be stored when a job is created
     public static final Set<String> HEADER_FILTERS =