PYCBC-134: Don't crash if passed duplicate keys

Some additional properties in Connection to test

Change-Id: I306dfedba0376fca59968db016dac6797257a135
Reviewed-on: http://review.couchbase.org/26989
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mordechai Nunberg <mnunberg@haskalah.org>