[#787] morph: Return VUB from Invoke method

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/morph/client/netmap/innerring.go

@@ -34,7 +34,8 @@ func (c *Client) UpdateInnerRing(p UpdateIRPrm) error {
 	prm.SetArgs(args)
 	prm.InvokePrmOptional = p.InvokePrmOptional
 
-	return c.client.Invoke(prm)
+	_, err := c.client.Invoke(prm)
+	return err
 }
 
 // GetInnerRingList return current IR list.