It is more efficient to provide a boundary value than a row count range.
This fixes replication on partitions with a large number of objects, revisions
or transactions: query time is now constant where it used to increase, causing
timeout problems when query duration exceeded ping time + ping timeout (11s
currently).

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2221 71dcc9de-d417-0410-9af5-da40c76e7ee4