Python: Switch postgres driver
Python: Switch postgres driver

The old driver (psycopg2) requires some development packages to be
installed. The new driver (pg8000) is pure python so it's much
easier to setup. Potentially the new driver is slower but we don't
need much performance from the postgres driver.

Change-Id: Iea743b53b20e9bdf405be595ab1cac35763f120b
Reviewed-on: http://gerrit.cloudera.org:8080/653
Reviewed-by: Taras Bobrovytsky <72e4a6fc4c5ef23f318dc209e8402725249a5676@cloudera.com>
Tested-by: Casey Ching <77bc9a9984e6786c5799d7a71768cf023120ef76@cloudera.com>

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