veyron/services/mgmt/node: adding log output for debugging node
manager on GCE

Change-Id: I17b547d11cc55d1f2da5491648d311b98d11dfb8
diff --git a/services/mgmt/node/impl/invoker.go b/services/mgmt/node/impl/invoker.go
index 819bf73..77744a3 100644
--- a/services/mgmt/node/impl/invoker.go
+++ b/services/mgmt/node/impl/invoker.go
@@ -420,6 +420,7 @@
 		vlog.Errorf("WriteFile(%v) failed: %v", path, err)
 		return errOperationFailed
 	}
+	vlog.VI(1).Infof("%s", output)
 	return nil
 }