Drop configure_tls northd workaround

The ovn-northd daemon has gained support for runtime reload of
certificate data [0] and is now on par with the other OVS/OVN
daemons.

Remove the workaround from the charm.

0: https://github.com/ovn-org/ovn/commit/8de4f8005f210
Closes-Bug: #1895303
Change-Id: I7f45b36e03b985ba2d170ead391615f9ef9dad8e

src/lib/charm/openstack/ovn_central.py

@@ -406,26 +406,20 @@ class BaseOVNCentralCharm(charms_openstack.charm.OpenStackCharm):
         tls_objects = self.get_certs_and_keys(
             certificates_interface=certificates_interface)
 
-        with charms_openstack.charm.utils.is_data_changed(
-                'configure_tls.tls_objects', tls_objects) as changed:
-            for tls_object in tls_objects:
-                with open(
-                        self.options.ovn_ca_cert, 'w') as crt:
-                    chain = tls_object.get('chain')
-                    if chain:
-                        crt.write(tls_object['ca'] + os.linesep + chain)
-                    else:
-                        crt.write(tls_object['ca'])
+        for tls_object in tls_objects:
+            with open(
+                    self.options.ovn_ca_cert, 'w') as crt:
+                chain = tls_object.get('chain')
+                if chain:
+                    crt.write(tls_object['ca'] + os.linesep + chain)
+                else:
+                    crt.write(tls_object['ca'])
 
-                self.configure_cert(self.ovn_sysconfdir(),
-                                    tls_object['cert'],
-                                    tls_object['key'],
-                                    cn='host')
-                if changed:
-                    # The `ovn-northd` daemon will not detect changes to the
-                    # certificate data and needs to be restarted. LP: #1895303
-                    self.service_reload('ovn-northd')
-                break
+            self.configure_cert(self.ovn_sysconfdir(),
+                                tls_object['cert'],
+                                tls_object['key'],
+                                cn='host')
+            break
 
     def configure_ovn_listener(self, db, port_map):
         """Create or update OVN listener configuration.

unit_tests/test_lib_charms_ovn_central.py

@@ -224,10 +224,6 @@ class TestOVNCentralCharm(Helper):
             'ca': 'fakeca',
             'chain': 'fakechain',
         }]
-        self.patch_target('service_reload')
-        self.patch('charms_openstack.charm.utils.is_data_changed',
-                   name='is_data_changed')
-        self.is_data_changed().__enter__.return_value = False
         with mock.patch('builtins.open', create=True) as mocked_open:
             mocked_file = mock.MagicMock(spec=io.FileIO)
             mocked_open.return_value = mocked_file
@@ -242,10 +238,6 @@ class TestOVNCentralCharm(Helper):
                 'fakecert',
                 'fakekey',
                 cn='host')
-            self.assertFalse(self.service_reload.called)
-            self.is_data_changed().__enter__.return_value = True
-            self.target.configure_tls()
-            self.service_reload.assert_called_once_with('ovn-northd')
 
     def test_configure_ovn_listener(self):
         self.patch_object(ovn_central.ch_ovsdb, 'SimpleOVSDB')