Improved error message on dbapi tests
Improved error message on dbapi tests

bhtucker/impyla,mariusvniekerk/impyla,wesm/impyla,laserson/impyla,mariusvniekerk/impyla,cloudera/impyla,schaffino/impyla,schaffino/impyla,bhtucker/impyla,mariusvniekerk/impyla,wesm/impyla,cloudera/impyla,laserson/impyla,bhtucker/impyla