NameError: name 'heightstr' is not defined after failing to fetch DEM tiles

[asjohnston-asf]

Six jobs failed with this error in a recent performance test:

https://hyp3-lavas-test.asf.alaska.edu/jobs/430c6fa5-1480-46d2-93d5-206ff3531b5a
https://hyp3-lavas-test.asf.alaska.edu/jobs/5550ac99-65fa-443d-8864-55d8846c83a4
https://hyp3-lavas-test.asf.alaska.edu/jobs/dc24f795-af3c-4f1e-8dbc-5dcdc24a9e79
https://hyp3-lavas-test.asf.alaska.edu/jobs/feae87b6-23f9-40bb-bcd9-4b3af19771c4
https://hyp3-lavas-test.asf.alaska.edu/jobs/d77c0950-7f9f-48c1-a3eb-e27c6477e2dd
https://hyp3-lavas-test.asf.alaska.edu/jobs/11f11f51-a7a9-4799-aae4-2220f130276b

These jobs are all for scenes over the midwest that should have DEM coverage. I suspect a bug in the DEM fetching code, possibly a networking error not being handled intelligently.

Example log file:
dc24f795-af3c-4f1e-8dbc-5dcdc24a9e79.log