rendercheck: background should be cleared when drawing trapezoids.

[Vikram Fugro]

Adding more,  the issue was only for operators like Src, Clear, In, Out, AtopReverse, InReverse,
with rendercheck tests failing for the above operators in triangles use case.
The snapshots were taken with Src operator.

________________________________________
From: Vikram Fugro
Sent: Tuesday, April 30, 2013 6:59 PM
To: xorg-devel at lists.freedesktop.org
Subject: rendercheck: background should be cleared when drawing trapezoids.

Hi all,

With the recent pixman library, trapezoid drawing on background has been fixed
by clearing the background (instead of retaining the color of the background).

I have done the necessary changes in the triangles use case (in rendercheck)
for the "color expected" from the background.

Attaching the patch and the snapshots for reference.

Thanks,
Vikram