netipmid: use std variant interface

Update code to remove mapbox-style interface usages.

Tested-by: run ipmitool to start a remote connection. See that sessions
           can be started, same as before change.

Change-Id: Ifc1a30069b6dc4e2d3706e1ca93f6b965552a051
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
1 file changed