MB-10957: Add python-snappy module

Change-Id: If6ea5a446d4f88e06dc294a2a4697cf3c30672a8
Reviewed-on: http://review.couchbase.org/37626
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>