Discovery create_collection must send JSON

[bruceadams]

This fixes the problem described here:
https://stackoverflow.com/questions/44707586/watson-discovery-service-create-collection-api-call-returns-error-415-unsuppo

[CLAassistant]

All committers have signed the CLA.

[codecov-io]

Codecov Report

Merging #223 into master will decrease coverage by 2.82%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #223      +/-   ##
==========================================
- Coverage   84.31%   81.49%   -2.83%     
==========================================
  Files          24       24              
  Lines        1167     1167              
==========================================
- Hits          984      951      -33     
- Misses        183      216      +33

Impacted Files	Coverage Δ
watson_developer_cloud/discovery_v1.py	100% <ø> (ø)	⬆️
watson_developer_cloud/language_translator_v2.py	44.82% <0%> (-31.04%)	⬇️
..._developer_cloud/watson_developer_cloud_service.py	63.54% <0%> (-9.38%)	⬇️
watson_developer_cloud/tone_analyzer_v3.py	92.3% <0%> (-7.7%)	⬇️
watson_developer_cloud/dialog_v1.py	38.88% <0%> (-5.56%)	⬇️
watson_developer_cloud/document_conversion_v1.py	93.75% <0%> (-3.13%)	⬇️

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[stevemar]

Since this is now merged, will this fix trigger a new release of the library?

[ltfschoen]

@stevemart I don't think it will automatically. I'm using Python 3.6.0 and watson-developer-cloud==0.26.0, but I just got the error WatsonException: Error: Unsupported Media Type, Code: 415 in my Jupyter Notebook, so I suspect this Pull Request that was merged 8 days ago isn't published yet on Python Package Index (PyPI) https://pypi.python.org/pypi/watson-developer-cloud?. It says my current version 0.26.0 was last updated to PyPI on 16 May 2017. I had to manually edit my file /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/watson_developer_cloud/discovery_v1.py with the file changes performed in this Pull Request and then restarted my Jupyter Notebook and the error went away.

[stevemar]

@ltfschoen perhaps "trigger" was the wrong word, I was trying to subtly ask the maintainers for a new release (0.27.0) :)