Add back guice binding for ZenPing

This should be removed, but some tests still rely on it being availale
from the injector in order to mess with it.

core/src/main/java/org/elasticsearch/discovery/DiscoveryModule.java

@@ -53,6 +53,7 @@ public class DiscoveryModule {
         new Setting<>("discovery.zen.hosts_provider", (String)null, Optional::ofNullable, Property.NodeScope);
 
     private final Discovery discovery;
+    private final ZenPing zenPing;
 
     public DiscoveryModule(Settings settings, ThreadPool threadPool, TransportService transportService, NetworkService networkService,
                            ClusterService clusterService, Function<UnicastHostsProvider, ZenPing> createZenPing,
@@ -78,7 +79,7 @@ public class DiscoveryModule {
             hostsProvider = Collections::emptyList;
         }
 
-        final ZenPing zenPing = createZenPing.apply(hostsProvider);
+        zenPing = createZenPing.apply(hostsProvider);
 
         Map<String, Supplier<Discovery>> discoveryTypes = new HashMap<>();
         discoveryTypes.put("zen",
@@ -102,4 +103,9 @@ public class DiscoveryModule {
     public Discovery getDiscovery() {
         return discovery;
     }
+
+    // TODO: remove this, it should be completely local to discovery, but service disruption tests want to mess with it
+    public ZenPing getZenPing() {
+        return zenPing;
+    }
 }

core/src/main/java/org/elasticsearch/discovery/zen/ZenDiscovery.java

@@ -138,7 +138,6 @@ public class ZenDiscovery extends AbstractLifecycleComponent implements Discover
     private volatile NodeJoinController nodeJoinController;
     private volatile NodeRemovalClusterStateTaskExecutor nodeRemovalExecutor;
 
-    @Inject
     public ZenDiscovery(Settings settings, ThreadPool threadPool, TransportService transportService,
                         ClusterService clusterService, ClusterSettings clusterSettings, ZenPing zenPing) {
         super(settings);

core/src/main/java/org/elasticsearch/node/Node.java

@@ -445,6 +445,7 @@ public class Node implements Closeable {
                         indicesModule.getMapperRegistry(), settingsModule.getIndexScopedSettings()));
                     b.bind(ClusterInfoService.class).toInstance(clusterInfoService);
                     b.bind(Discovery.class).toInstance(discoveryModule.getDiscovery());
+                    b.bind(ZenPing.class).toInstance(discoveryModule.getZenPing());
                     {
                         RecoverySettings recoverySettings = new RecoverySettings(settings, settingsModule.getClusterSettings());
                         processRecoverySettings(settingsModule.getClusterSettings(), recoverySettings);