Set srcRepeat = False when using fbCompositeSrcScaleNearest

Set srcRepeat = False when using fbCompositeSrcScaleNearest

NORMAL repeat was broken (the optimized function can handle repeat operation
itself and can be screwed up if 'pixman_walk_composite_region' tries to help it
by splitting the work into handling multiple separate areas).

Splitting work into handling different areas does not work right for the
transform case (and it is never used for generic path).  The point is that this
splitting only has full pixel precision at the moment, while correct blitting
needs to preserve some fractional part in calculations when moving from one
"tile" to another.