CBQE-2458: fix update dml tests

Change-Id: I84137d26b6f8635da1bc486f78ad34f4f8c77cdd
Reviewed-on: http://review.couchbase.org/43567
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>