CBQE-1407: sasl password tests

Change-Id: I30774ed48bdd51b1388e3b8120abed386523405a
Reviewed-on: http://review.couchbase.org/28435
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>