Update ovn train candidate to 2.11.0-9
Update ovn train candidate to 2.11.0-9

ovn-2.11.0-9 has epoch fix which is required for
obsoleting openvswitch-ovn* packages.

Change-Id: I09d958d8e7c22132fd8ed57f2e367558f6928359

redhat-openstack/rdoinfo,javierpena/rdoinfo