MB-100: Mods in xdcrbasetests

Change-Id: Ibb2120248daaa9775cf0cd51504a993c5e7baf3b
Reviewed-on: http://review.couchbase.org/25821
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>
Tested-by: buildbot <build@couchbase.com>
Tested-by: abhinav dangeti <abhinav.dangeti@gmail.com>