Fix password authentication in worker (#3124)

python/ray/services.py

@@ -1227,6 +1227,8 @@ def start_raylet_monitor(redis_address,
     gcs_ip_address, gcs_port = redis_address.split(":")
     redis_password = redis_password or ""
     command = [RAYLET_MONITOR_EXECUTABLE, gcs_ip_address, gcs_port]
+    if redis_password:
+        command += [redis_password]
     p = subprocess.Popen(command, stdout=stdout_file, stderr=stderr_file)
     if cleanup:
         all_processes[PROCESS_TYPE_MONITOR].append(p)