Update interface that should be turned off in ha_disconnect_controllers test

The test turn off interface used by management network.
Management network is on eth2 but it turned off eth3.
The commit changes interface name from eth3 to eth2.

Change-Id: Ifb1203cc25ebd6182658e108a9676ebc98c13c98
Merge "Update interface that should be turned off in ha_disconnect_controllers test"