CBQE-0: added tests for flush/delete/re-created destination buckets in
XDCR

Change-Id: Iac6d5ad9fc0e9f18e9c19844fcf0ae601e17e0cb
Reviewed-on: http://review.couchbase.org/36777
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>