vagrant: Run ovnkube with nohup on minions
vagrant: Run ovnkube with nohup on minions

With -nodeport as an option, we should run ovnkube in
background with a nohup.

Signed-off-by: Gurucharan Shetty <a1872e333d0e52644f6125da2276530f7ebe5e77@ovn.org>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes