Fix expect_timeout_error in IPv6 scenario tests

Fix except_timeout_error call to make_request. In case of an IPv6
address and a TCP-based protocol, make_request expects brackets around
the address (ex: [2001:12::2]).

Some tests failed with the following error: "Validate URL got exception:
Failed to parse: http://fd22:262a:41e1:1::f5:97. Retrying.". Then the
requests timed out because each retry failed and not for the excepted
reason (which is: SG update was applied)
Because of that issue, some IPv6 tests based on
_test_listener_with_allowed_cidrs may have failed because the tests
considered that the SG were applied, while the traffic could still pass.

Change-Id: I2e6d108a8d4ce197ae657ea10b10f63b1a5850c4

octavia_tempest_plugin/tests/scenario/v2/test_ipv6_traffic_ops.py

@@ -493,6 +493,8 @@ class IPv6TrafficOperationsScenarioTest(
         # wait until Neutron completes the SG update.
         # See https://bugs.launchpad.net/neutron/+bug/1866353.
         def expect_timeout_error(address, protocol, protocol_port):
+            if protocol != const.UDP:
+                address = "[{}]".format(address)
             try:
                 self.make_request(address, protocol=protocol,
                                   protocol_port=protocol_port)