Add manual ovs upgrade script for workaround ovs upgrade issue

Add manual ovs upgrade script for workaround ovs upgrade issue

When we upgrade OVS from 2.5 to 2.6, the postrun package update
restart the services and drop the connectivity
We need to push this manual upgrade script and executed to the
nodes for newton to ocata

The special case is needed for 2.5.0-14 specifically see related
bug for more info (or, older where the postun tries restart).
See related review at [1] for the minor update/manual upgrade.

Related-Bug: 1669714
Depends-On: I3227189691df85f265cf84bd4115d8d4c9f979f3
Co-Authored-By: Sofer Athlan-Guyot <sathlang@redhat.com>
[1] https://review.openstack.org/#/c/450607/

Change-Id: If998704b3c4199bbae8a1d068c31a71763f5c8a2