If rhosydd-client is running on the same machine as isolation.py is run
on, its network and mount namespaces will cause the test to fail, as it
uses the standard namespaces, and hence makes the test think that an
important part of Rhosydd is (erroneously) using the standard
namespaces.

rhosydd-client itself doesn’t need to use mount namespaces as it doesn’t
have access to any more data than any other consumer of the sensors and
actuators SDK API.

rhosydd-client could be running on the machine while the tests are
running if a developer is doing multiple things at once.

Reviewed-by: Mathieu Duponchelle <mathieu.duponchelle@collabora.co.uk>
Signed-off-by: Philip Withnall <philip.withnall@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D3725