fixes a bug where json_data_structure caches spot data that could be inaccurate
fixes a bug where json_data_structure caches spot data that could be inaccurate

fixes SPOT-940

omg. this was the most complex thing ive had to debug. basically, spot json
was being cached with an etag that was a couple etags behind

uw-it-aca/spotseeker_server,uw-it-aca/spotseeker_server,uw-it-aca/spotseeker_server