RuntimeWarning in cpppo.enip.client

[noleti]

As noted in #30 as part of the bug report, with cpppo 4.3.4 we now get warnings such as the following from the plcs in the example:

logs/plc2.log:/usr/lib/python3.8/runpy.py:127: RuntimeWarning: 'cpppo.server.enip.client' found in sys.modules after import of package 'cpppo.server.enip', but prior to execution of 'cpppo.server.enip.client'; this may result in unpredictable behaviour

While this does not appear to impact the execution, the warning should be addressed at some point.