XCopyArea clip bug

[Maarten Maathuis]

I comitted a slightly different patch.

I found out that all clipping possibilities are converted to regions
in the end, so this should be enough.

http://cgit.freedesktop.org/xorg/xserver/commit/?id=00226d0b589595cdd45c75e7e28237334a8883b1

You can put the patch on the wiki
(http://wiki.x.org/wiki/Server16Branch) for xserver 1.6 inclusion if
you are seriously bothered by the issue.

Maarten.