FileManagerTest: account for retry in the timeout
FileManagerTest: account for retry in the timeout

Hunter522/qgroundcontrol,ethz-asl/qgc_asl,Hunter522/qgroundcontrol,Hunter522/qgroundcontrol,ethz-asl/qgc_asl,ethz-asl/qgc_asl,Hunter522/qgroundcontrol,Hunter522/qgroundcontrol,ethz-asl/qgc_asl,Hunter522/qgroundcontrol,ethz-asl/qgc_asl