Grenade jobs stop services, check fip connectivity
for a nova server and then upgrade to next release.
But since ovn data plane and db services are stopped along
with other services, fip connectivity fails as a result.
We shouldn't stop these services along with other
neutron services. This patch sets "SKIP_STOP_OVN" to True
to skip stop of ovn services.
This fixes ovn grenade jobs.
Depends-On: https://review.opendev.org/c/openstack/devstack/+/839362
Change-Id: I2bd3f7e5f0af9a6532db7a1cdb4bc45a963042ca