PM-961 update example to refer to PEGASUS_SCRATCH_DIR instead of _PEGASUS_SCRATCH_DIR
PM-961 update example to refer to PEGASUS_SCRATCH_DIR instead of _PEGASUS_SCRATCH_DIR

pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus