PYCBC-207: Support gevent 1.0

Change-Id: I5f406eda4f1fa4896af648c5f8d16ae9da114ecb
Reviewed-on: http://review.couchbase.org/30810
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>