Fix P4RuntimeClientImpl sending empty stream RPC messages

Change-Id: I31e010144585a0cb9e054e773b7a7e4380919d75
diff --git a/protocols/p4runtime/api/src/main/java/org/onosproject/p4runtime/api/P4RuntimeClient.java b/protocols/p4runtime/api/src/main/java/org/onosproject/p4runtime/api/P4RuntimeClient.java
index 93adf11..32b1f9f 100644
--- a/protocols/p4runtime/api/src/main/java/org/onosproject/p4runtime/api/P4RuntimeClient.java
+++ b/protocols/p4runtime/api/src/main/java/org/onosproject/p4runtime/api/P4RuntimeClient.java
@@ -54,7 +54,8 @@
     }
 
     /**
-     * Starts the client by starting the Stream RPC with the device.
+     * Starts the client by starting the Stream RPC with the device. The
+     * implementation of this method is equivalent to {@link #becomeMaster()}.
      *
      * @return completable future containing true if the operation was
      * successful, false otherwise.
diff --git a/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/P4RuntimeClientImpl.java b/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/P4RuntimeClientImpl.java
index b4d88a7..a5c3c13 100644
--- a/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/P4RuntimeClientImpl.java
+++ b/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/P4RuntimeClientImpl.java
@@ -207,7 +207,7 @@
 
     @Override
     public CompletableFuture<Boolean> start() {
-        return supplyInContext(this::doInitStreamChannel,
+        return supplyInContext(this::doBecomeMaster,
                                "start-initStreamChannel");
     }
 
@@ -356,20 +356,6 @@
         return false;
     }
 
-    private boolean doInitStreamChannel() {
-        // To listen for packets and other events, we need to start the RPC.
-        // Here we send an empty StreamMessageRequest.
-        try {
-            log.info("Starting stream channel with {}...", deviceId);
-            streamRequestObserver.onNext(StreamMessageRequest.newBuilder().build());
-            return true;
-        } catch (StatusRuntimeException e) {
-            log.error("Unable to start stream channel with {}: {}",
-                      deviceId, e.getMessage());
-            return false;
-        }
-    }
-
     private boolean doSetPipelineConfig(PiPipeconf pipeconf, ByteBuffer deviceData) {
 
         log.info("Setting pipeline config for {} to {}...", deviceId, pipeconf.id());