(minor) nosetests runs off of user's current config; should be mocked

[p5k6]

At least, I would assume so. Got an error message that postgres wasn't configured when running nosetests. (my personal config does not have anything set up for postgres, as I'm working on mysql => Redshift at the moment).

Adding dummy info (from example config) to my ~/.dataduct/dataduct.cfg allowed tests to run, but I would assume that this data should be mocked out for tests.