Catch case changes in file names when harvesting

[janette]

QA Steps

• copy the h1.json.txt file from this ticket (drop the .txt) to your /src/site/files directory
• run dktl drush dkan:harvest:register '\{"identifier":"h1","extract":{"type":"\\Harvest\\ETL\\Extract\\DataJson","uri":"http://dkan.localtest.me/sites/default/files/h1.json"},"transforms":[],"load":\{"type":"\\Drupal\\harvest\\Load\\Dataset"}}'
• then dktl drush dkan:harvest:run h1
• look at the harvested dataset in the edit form, notice the case of the filename
• edit the h1.json file: change downloadURL to

"http://demo.getdkan.org/sites/default/files/distribution/cedcd327-4e5d-43f9-8eb1-c11850fa7c55/bike_lane.csv"

• run the harvest again
• look at the dataset in the edit form, confirm the filepath was updated

h1.json.txt

[dafeder]

This could be QA'ed with just a simple API call starting with one URL than patching with another, right? Not harvest-specific. I added a quick unit test.