Only handle dead letters to addresses, not connection info.

// FREEBIE

src/main/java/org/whispersystems/textsecuregcm/websocket/DeadLetterHandler.java

@@ -20,8 +20,9 @@ public class DeadLetterHandler implements DispatchChannel {
 
   @Override
   public void onDispatchMessage(String channel, byte[] data) {
+    if (!WebSocketConnectionInfo.isType(channel)) {
       try {
-      logger.warn("Handling dead letter to: " + channel);
+        logger.info("Handling dead letter to: " + channel);
 
         WebsocketAddress address       = new WebsocketAddress(channel);
         PubSubMessage    pubSubMessage = PubSubMessage.parseFrom(data);
@@ -38,6 +39,7 @@ public class DeadLetterHandler implements DispatchChannel {
         logger.warn("Invalid websocket address", e);
       }
     }
+  }
 
   @Override
   public void onDispatchSubscribed(String channel) {

src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionInfo.java

@@ -33,6 +33,10 @@ public class WebSocketConnectionInfo implements PubSubAddress {
     return address;
   }
 
+  public static boolean isType(String address) {
+    return address.endsWith(":c");
+  }
+
   @Override
   public boolean equals(Object other) {
     return