Add host validation after live migration

test_server_connectivity_live_migration was passing even in case
live migration was aborted e.g. like in case documented in [1].
This patch adds validation that server actually migrated.

[1] https://bugs.launchpad.net/tripleo/+bug/1852064

Change-Id: If6493ec4c849618fdd52a7e725f44537ab33d16a
diff --git a/tempest/scenario/test_network_advanced_server_ops.py b/tempest/scenario/test_network_advanced_server_ops.py
index f03e9de..b1919d4 100644
--- a/tempest/scenario/test_network_advanced_server_ops.py
+++ b/tempest/scenario/test_network_advanced_server_ops.py
@@ -249,12 +249,16 @@
 
         block_migration = (CONF.compute_feature_enabled.
                            block_migration_for_live_migration)
+        old_host = self.get_host_for_server(server['id'])
         self.admin_servers_client.live_migrate_server(
             server['id'], host=None, block_migration=block_migration,
             disk_over_commit=False)
         waiters.wait_for_server_status(self.servers_client,
                                        server['id'], 'ACTIVE')
 
+        new_host = self.get_host_for_server(server['id'])
+        self.assertNotEqual(old_host, new_host, 'Server did not migrate')
+
         self._wait_server_status_and_check_network_connectivity(
             server, keypair, floating_ip)