Fix a content join condition in Phriction

After the cursor changes, we may fatal on pages with a large number of children
because "c.title" is not a selected column. We currently join the "content"
table if "updated" is part of the order vector, but not if "title" is part of
the order vector. This isn't right: "updated" is on the primary table, and only
"content" is on the joined table.