Revert "MB-10471: The chk low seqno should be set to the chk start item"

This reverts commit 488d87a925c86c283b07eacf38c95f4b071ef72b.

Change-Id: I320d0ddc3e259a9f5f3feec721152c0bdb0b5945
Reviewed-on: http://review.couchbase.org/34946
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>