PYCBC-550: Correct txcouchbase get_multi example
PYCBC-550: Correct txcouchbase get_multi example

Change-Id: Iae7d75db8740cc0fa5bd7742827d3a50c5d7d739
Reviewed-on: http://review.couchbase.org/102105
Reviewed-by: David Haikney <429c6ca43f70a1a1104bd68d6b2835bd23bff953@couchbase.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

couchbase/couchbase-python-client,couchbase/couchbase-python-client