If there are multiple blog posts or tasks with exactly the same
creation or completion time, the same blog post can appear on two
different pages of results, because the the order by part of the query
is not restrictive enough to produce an unambiguous order.

Change-Id: I59a7110b49e92af1a05dba37379707ea9fc225ef
Signed-off-by: Richard Mansfield <richard.mansfield@catalyst.net.nz>