CBQE-2369: add  xdcr+hostname tests

Change-Id: I1dbcbf073ec17a32aea83f746dbce44c36a2f37e
Reviewed-on: http://review.couchbase.org/40338
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: buildbot <build@couchbase.com>