Regression: DropShadows broken

ebf3ea32e637e352f8afdcc54979515f8adb9945 is the first bad commit
commit ebf3ea32e637e352f8afdcc54979515f8adb9945
Author: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Date:   Mon Jan 26 08:14:29 2015 +0100

    Implement DropShadow using the new gaussian blur.
    
    The 'fast' path has been discarded because it fails to deliver on
    the fast promise. For radii less than 30-40 the normal blur is faster,
    so little point
    
    [ChangeLog] DropShadow uses the new gaussian blur
    implementation. 'fast' no longer has any effect. The default values
    have been updated so that 'layer.effect: DropShadow { }' works out of
    the box.
    
    Change-Id: I7e4ace4623613f0969a35e0c9bb873c18a158450
    Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>