[FT] Mark test_fip_connection_for_address_scope unstable

The test is failing randomly from quite some time now,
marking this unstable until this gets fixed.

Related-Bug: #2115026
Change-Id: Idff5aa32df45592992312347ad2eaa424391909a
Signed-off-by: yatinkarel <[email protected]>
(cherry picked from commit 5454e76)

Author: karelyatin

neutron/tests/functional/agent/l3/test_dvr_router.py

@@ -32,6 +32,7 @@
 from neutron.agent.linux import ip_lib
 from neutron.agent.linux import iptables_manager
 from neutron.common import utils
+from neutron.tests import base as test_base
 from neutron.tests.common import l3_test_common
 from neutron.tests.common import machine_fixtures
 from neutron.tests.common import net_helpers
@@ -2180,6 +2181,7 @@ def test_connection_from_diff_address_scope(self):
         test_machine1.assert_no_ping(test_machine2.ip)
         test_machine2.assert_no_ping(test_machine1.ip)
 
+    @test_base.unstable_test('bug 2115026')
     def test_fip_connection_for_address_scope(self):
         self.agent.conf.agent_mode = 'dvr_snat'
         (machine_same_scope, machine_diff_scope,