Even if you don't need a parameter for extractor, it doesn't work without parameter

[ddey2]

Steps to reproduce:

1. Create an extractor
2. In extractor_info.json, don't put a parameter
3. Run the extractor and submit a jot
   You should see the following error:

If you put the empty parameter in extractor_info.json, it works. You need the entire structure.
"parameters": {
"schema": {
},
"form": []
}

[tcnichol]

Is there an extractor that produces this bug? I notice most of the ones in pyclowder don't use parameters. Is there some other extractor that I can test with to replicate?