Range: Fix inverted vert scrolling on horiz Ranges

Range: Fix inverted vert scrolling on horiz Ranges

Users expect, & previous patches have tried to assure, that scrolling up
over a horizontal Range will cause the value to increase & vice-versa.
But the path using directions was still negating the delta & decreasing
the value on scrolling up. This could be seen on Win32 or X without XI2.

So, only negate the delta when scrolling down (or left), not up, so that
scrolling up (or right) will make the value increase for any event type.

https://bugzilla.gnome.org/show_bug.cgi?id=737175#c5