Fixed bug running DUT fuzzing image cleanup script on Ubuntu vs MacOS.
Fixed bug running DUT fuzzing image cleanup script on Ubuntu vs MacOS.

Signed-off-by: timothytrippel <580026a4889dc6e41b7e2d433baf68cf23e8b590@umich.edu>

googleinterns/hw-fuzzing,googleinterns/hw-fuzzing,googleinterns/hw-fuzzing,googleinterns/hw-fuzzing