igb driver : emit a message on ifdown

Issue

• Not getting link down messages in /var/log/messages.
• If we make down the non-bonded interfaces ,we are not getting the link down messages in /var/log/messages. Why igb driver is not responding for link down.

>> ifdown eth4
No messages

>> ifup eth4
May 21 08:51:06 hostname kernel: igb: eth4 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
May 21 08:51:06 hostname kernel: ADDRCONF(NETDEV_UP): eth4: link is not ready
May 21 08:51:06 hostname kernel: 8021q: adding VLAN 0 to HW filter on device eth4
May 21 08:51:06 hostname kernel: ADDRCONF(NETDEV_CHANGE): eth4: link becomes ready

• If a cable is pulled from an igb NIC, the syslog receives a "Link down" message. But if an ifdown is performed on the same igb NIC, there is no message.