Fix off-by-one error in the "previous 200" link in category listings

Fix off-by-one error in the "previous 200" link in category listings
with until=param

When an until parameter is given i.e. going to a previous page, the
category page does the sql query in descending order. In that case,
the previous page link was given an until paramter that was one more
than the last needed result, since until= is interpreted as up-to but
not including, unlike from=, which is starting from and including.

Bug: 36964
Change-Id: I7eaf58d78136ac069a2d9122bca03f87863d2c0b