MB-9503: list all xdcr replications

Change-Id: Iab4dc1fdef541cc5677f22244a8e9ff9ac279a92
Reviewed-on: http://review.couchbase.org/30453
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>