[PING] Don't bubble up exception if we are shutting down and ping schedules get rejected

Author: s1monw

src/main/java/org/elasticsearch/discovery/zen/ping/unicast/UnicastZenPing.java

@@ -35,6 +35,7 @@
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
+import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
 import org.elasticsearch.discovery.zen.elect.ElectMasterService;
 import org.elasticsearch.discovery.zen.ping.PingContextProvider;
 import org.elasticsearch.discovery.zen.ping.ZenPing;
@@ -254,6 +255,9 @@ public void run() {
                     }
                 }
             });
+        } catch (EsRejectedExecutionException ex) { // TODO: remove this once ScheduledExecutor has support for AbstractRunnable
+            sendPingsHandler.close();
+            // we are shutting down
         } catch (Exception e) {
             sendPingsHandler.close();
             throw new ElasticsearchException("Ping execution failed", e);