lisa.wlgen.workload: Fix str conversion in wipe_run_dir
lisa.wlgen.workload: Fix str conversion in wipe_run_dir

My bad, something else was missing. Path().parent returns a PosixPath. We
need to convert it to a string before giving it to quote()

credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa