teststests/test_baseapi.py: POST test support py3
teststests/test_baseapi.py: POST test support py3

Fix python3 tests for POSTing to PuppetDB with the query
in the body. In python2, requests encodes the contents of
the request body as a string, but in python3, the body is
encoded as a bytes object.

Use the six.b() function to use the correct type when
comparing the expected value with the value that was sent.

Co-authored-by: Bill Ward <c692d6a10598e0a801576fdd4ecf3c37e45bfbc4@admintome.com>

voxpupuli/pypuppetdb,puppet-community/pypuppetdb