The following file(s) added utf-8 encoding but never used. So we can
remove them at all.
neutron_lib/__init__.py
neutron_lib/tests/unit/callbacks/test_callback_exceptions.py
neutron_lib/tests/unit/test_exceptions.py
neutron_lib/tests/unit/test_neutron_lib.py
releasenotes/source/conf.py
doc/source/conf.py
api-ref/source/conf.py
Change-Id: I45f1d48f8df461b67e6c37a37e0577ed4c1296a1