Remove redundant skip decorators for broadcast_rpc_port tests

The skip decorators referencing issue #121 were unnecessary because:

- test_control_connection_port_discovery: Already has @greaterthanorequalcass40
  which skips for Scylla (mapped to Cassandra 3.11.4)
- test_single_interface: The entire class has @greaterthanorequalcass40
- test_host_addresses: Port assertions are conditional on CASSANDRA_VERSION >= 4.0

Since Scylla's CASSANDRA_VERSION defaults to 3.11.4, these version checks
already prevent the port-related assertions from running on Scylla.

Fixes: #121

Author: dkropachev

tests/integration/standard/test_control_connection.py

@@ -108,8 +108,6 @@ def test_get_control_connection_host(self):
 
         assert new_host1 != new_host2
 
-    # TODO: enable after https://github.com/scylladb/python-driver/issues/121 is fixed
-    @unittest.skip('Fails on scylla due to the broadcast_rpc_port is None')
     @greaterthanorequalcass40
     def test_control_connection_port_discovery(self):
         """

tests/integration/standard/test_metadata.py

@@ -57,8 +57,6 @@ def setup_module():
 
 
 class HostMetaDataTests(BasicExistingKeyspaceUnitTestCase):
-    # TODO: enable after https://github.com/scylladb/python-driver/issues/121 is fixed
-    @unittest.skip('Fails on scylla due to the broadcast_rpc_port is None')
     @local
     def test_host_addresses(self):
         """

tests/integration/standard/test_single_interface.py

@@ -44,8 +44,6 @@ def tearDown(self):
         if self.cluster is not None:
             self.cluster.shutdown()
 
-    # TODO: enable after https://github.com/scylladb/python-driver/issues/121 is fixed
-    @unittest.skip('Fails on scylla due to the broadcast_rpc_port is None')
     def test_single_interface(self):
         """
         Test that we can connect to a multiple hosts bound to a single interface.