Skip WritableMtuTest for OVN

The test requires east/west fragmentation which
is currently not supported in core OVN.

Co-Authored-By: Yatin Karel <ykarel@redhat.com>
Change-Id: I2e6e0585fdcc984437a7913e80170889c797563c
Signed-off-by: Jakub Libosvar <libosvar@redhat.com>
diff --git a/zuul.d/master_jobs.yaml b/zuul.d/master_jobs.yaml
index 728eed8..072c8b4 100644
--- a/zuul.d/master_jobs.yaml
+++ b/zuul.d/master_jobs.yaml
@@ -196,9 +196,12 @@
       # TODO(slaweq): Remove test_trunk_subport_lifecycle test from the
       # blacklist when bug https://bugs.launchpad.net/neutron/+bug/1885900 will
       # be fixed
+      # TODO(jlibosva): Remove the NetworkWritableMtuTest test from the list
+      # once east/west fragmentation is supported in core OVN
       tempest_black_regex: "\
           (?:neutron_tempest_plugin.scenario.test_ipv6.IPv6Test)|\
-          (^neutron_tempest_plugin.scenario.test_trunk.TrunkTest.test_trunk_subport_lifecycle)"
+          (^neutron_tempest_plugin.scenario.test_trunk.TrunkTest.test_trunk_subport_lifecycle)|\
+          (^neutron_tempest_plugin.scenario.test_mtu.NetworkWritableMtuTest)"
       devstack_localrc:
         Q_AGENT: ovn
         NETWORK_API_EXTENSIONS: "{{ network_api_extensions | join(',') }}"