MB-10833: Add support for delta recovery buckets

Change-Id: Ia73d3c8ed4bafce2f9f67024654c56e0b72e0f3e
Reviewed-on: http://review.couchbase.org/35729
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>