CBQE-0: remove ddoc after each test

Change-Id: Ibeed7a165117299c687a6c9dd670b00cb9539bf5
Reviewed-on: http://review.couchbase.org/33252
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>