sdcm.tester: Remove extra is None condition
sdcm.tester: Remove extra is None condition

Although the second is None condition is valid python,
the entire expression will always evaluate to False and
was a mistake made during a rebase of one particular
Pull Request. Let's remove the extra condition.

Signed-off-by: Lucas Meneghel Rodrigues <8ad3460456640ab580599f5440c5a8d925a620b9@scylladb.com>

scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests