Don't install nova's rootwrap file in light mode
Don't install nova's rootwrap file in light mode

Since we don't install Nova in light mode, /etc/nova/rootwrap.d/
doesn't exist, thus stack.sh would fail.

Change-Id: Iabb41422d8daae5a52d03957d099d187f7e1a0ad

yamt/networking-midonet,yamt/networking-midonet