Remove `status=none' flag from `dd' invocation (backwards compatibility)
Remove `status=none' flag from `dd' invocation (backwards compatibility)

This is in response to the "dd: invalid status flag: none" error seen
here: https://travis-ci.org/xolox/python-linux-utils/jobs/245334722

xolox/python-linux-utils,xolox/python-linux-utils