[OVN] Blacklist test_port_security_macspoofing_port test

The test_port_security_macspoofing_port should be blacklisted
back, because of the change [1] that switched OVN_BRANCH/OVS_BRANCH
configuration to the latest stable releases and the
fix [2] that solved [3] is not yet present in latest release.

In addition. We will have discussion during next PTG around if we
should/could run only jobs with OVN release or we can enable also
master jobs. Then we need to explicitely define from which branch
given job runs to prevent such situations like this one in future.

[1] https://review.opendev.org/#/c/726168/
[2] https://patchwork.ozlabs.org/project/openvswitch/patch/20200319122641.473776-1-numans@ovn.org/
[3] https://bugs.launchpad.net/tempest/+bug/1728886

Related-Bug: #1728886

Change-Id: Ic8952e9ffb031ff4becb6ee2f6f5325a55e19dfe

zuul.d/tempest-multinode.yaml

@@ -212,7 +212,16 @@
       # tempest.scenario.test_network_v6.TestGettingAddress module from
       # blacklist when bug https://bugs.launchpad.net/neutron/+bug/1863577 will
       # be fixed
+      # TODO(mjozefcz): The test test_port_security_macspoofing_port
+      # and related bug https://bugs.launchpad.net/tempest/+bug/1728886
+      # are fixed in Core-OVN, but tempest-slow job uses stable release of
+      # core OVN now and thats why it is still failing in this job.
+      # Remove this blacklist when OVN 20.06 will be releaseed and consumed.
+      # In addition: on next PTG we will discuss the rules of running specific
+      # jobs with OVN master and OVN release branches. Please consider
+      # specyfing explicitely the version of OVN in tempest-slow jobs.
       tempest_black_regex: "\
+          (?:tempest.scenario.test_network_basic_ops.TestNetworkBasicOps.test_port_security_macspoofing_port)|\
           (^tempest.scenario.test_network_v6.TestGettingAddress)"