[VOL-4119] voltha-core incorrect args for Get-Onu-Image

Change-Id: Ibe99ab3956c1427584d5ba4f77693458342ad111
diff --git a/vendor/github.com/opencord/voltha-lib-go/v4/pkg/adapters/common/request_handler.go b/vendor/github.com/opencord/voltha-lib-go/v4/pkg/adapters/common/request_handler.go
index 020e799..b6cf1c0 100644
--- a/vendor/github.com/opencord/voltha-lib-go/v4/pkg/adapters/common/request_handler.go
+++ b/vendor/github.com/opencord/voltha-lib-go/v4/pkg/adapters/common/request_handler.go
@@ -852,8 +852,6 @@
 				logger.Warnw(ctx, "cannot-unmarshal-device", log.Fields{"error": err})
 				return nil, err
 			}
-		default:
-			return nil, errors.New("invalid argument")
 		}
 	}
 	return &deviceDownloadImageReq, nil
@@ -875,8 +873,6 @@
 				logger.Warnw(ctx, "cannot-unmarshal-device", log.Fields{"error": err})
 				return nil, err
 			}
-		default:
-			return nil, errors.New("invalid argument")
 		}
 	}
 	return &deviceImageReq, nil
@@ -894,10 +890,13 @@
 				logger.Warnw(ctx, "cannot-unmarshal-device", log.Fields{"error": err})
 				return "", err
 			}
-		default:
-			return "", errors.New("invalid argument")
 		}
 	}
+
+	if deviceId.Val == "" {
+		return "", errors.New("invalid argument")
+	}
+
 	return deviceId.Val, nil
 }