openvswitch: set IPS_CONFIRMED in tmpl status only when commit is set in conntrack

By not setting IPS_CONFIRMED in tmpl that allows the exp not to be removed
from the hashtable when lookup, we can simplify the exp processing code a
lot in openvswitch conntrack.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>