- Patch #18692 by Goba: old comments (comments for nodes having no entry in...

- Patch #18692 by Goba: old comments (comments for nodes having no entry in the history table anymore) are counted as new comments, since the timestamp retrieved from the history table is used to check for new comments (which is 0, if an entry was not found). This patch sets the timestamp used to check for new comments to the NODE_NEW_LIMIT value at least (which is when the history table was/should have been pruned).