Set the port status to a known state.
Set the port status to a known state.

Summary:
OpenNSL wants to default the port to enabled, which means that we never
actually do any of the necessary initialization to bring it up. If we
aren't warm booting, we should guarantee that the status is down before
we try to bring it up.

Reviewed By: aeckert

Differential Revision: D2826786

fb-gh-sync-id: 04e6bd6ec857ad635bee628785483677759f771d

peterlei/fboss,neuhausler/fboss,peterlei/fboss,neuhausler/fboss,neuhausler/fboss,peterlei/fboss,peterlei/fboss,neuhausler/fboss