add INFO level operation logging on each node.

Administrator couldn't track operation on each node without this function.
This function logs only administrative operation at rx_main and tx_main.
Operations that is not related to administrative operation are not
logged in this function. such as read/write etc.

Signed-off-by: Yoshinori Matsuo <matsuo.yoshinori@lab.ntt.co.jp>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>