CBQE-1107: add dgm test of replica read

Change-Id: I169029311d1b21c92067f611bb4c067dd18fce16
Reviewed-on: http://review.couchbase.org/25872
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>