Make neutron-openvswitch-agent run cleanup.

Whenever we install the neutron-openvswitch-agent we should
also install the ovs-cleanup utility.

1) cleanup any OVS ports created by neutron

2) Also cleanup other non-neutron created OVS ports as well. This is
 really important since we want to get a DHCP address on
 a reboot (DHCP fails early on since OVS isn't fully initialized).
 init-neutron will always move any NICs back the bridge anyway...

Change-Id: Id1fdab5337296b17865c0fff85a8852c03c7968a
Merge "Make neutron-openvswitch-agent run cleanup."