mark the python examples as having utf-8 encoding

src/python-lxc/examples/api_test.py

 #!/usr/bin/env python3
+# -*- coding: utf-8 -*-
 #
 # api_test.py: Test/demo of the python3-lxc API
 #

src/python-lxc/examples/pyconsole-vte.py

 #!/usr/bin/env python3
+# -*- coding: utf-8 -*-
 #
 # pyconsole-vte: Example program showing use of console functions
 #                in the lxc python binding

src/python-lxc/examples/pyconsole.py

 #!/usr/bin/env python3
+# -*- coding: utf-8 -*-
 #
 # pyconsole: Example program showing use of console functions
 #            in the lxc python binding