Error page after trying to download data from search page in web UI

[dlebauer]

When I go to betydb.org (or do similar w/ terraref.ncsa.illinois.edu/bety) and I

1. enter "panicum sla" into the search box and hit return
   • the results show up as expected
2. on the results page, when I click 'download results'
   • I expect a CSV of the results to be downloaded
   • instead, I get an error:

Is this a known bug? Related to rails updates?

Version info: Branch:master Date:Mon Aug 27 11:23:39 2018 -0400 Checksum:8380cf0