remove obsolete helper

seems to be a leftover, obsoleted by the simplifications done this june
in c80b1894e6 Ticket #641

src/proc/mobject/session/scope-query.hpp

@@ -184,12 +184,6 @@ namespace session {
         {
           return bind (&PlacementMO::isCompatible<MO>, _1 );
         }
-      
-      void
-      resetResultIteration (iterator const& newQueryResults)
-        {
-          static_cast<iterator&> (*this) = newQueryResults;
-        }
     };