MB-12179: Remove the old dump API's from the KVStore

We should now use the scan API's that were added in the previous
patch-sets.

Change-Id: I788aee255a3d8e87e8f6dff938a15bbe054038a6
Reviewed-on: http://review.couchbase.org/41833
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>