Improve query for unscored previous revisions
Improve query for unscored previous revisions

Excluding known initial revisions will prevent running some queries over and over again.

WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard