[#170] morph/client: Print reversed hash in logs

JSON-RPC method takes reversed hash as an input so it is
better to output reveresed hash in logs.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/morph/client/client.go

@@ -81,7 +81,7 @@ func (c *Client) Invoke(contract util.Uint160, fee util.Fixed8, method string, a
 
 	c.logger.Debug("neo client invoke",
 		zap.String("method", method),
-		zap.Stringer("tx_hash", txHash))
+		zap.Stringer("tx_hash", txHash.Reverse()))
 
 	return nil
 }