Revert "clutter-cairo-texture: Use the new cogl_pixel_buffer API"

Revert "clutter-cairo-texture: Use the new cogl_pixel_buffer API"

This reverts commit 716ec82db8bec57e35d51e8dee5468435fc9e59e.

The Cogl pixel buffer API currently has problems if an atlas texture
is created or the format needs to be converted. The atlas problem
doesn't currently show because the atlas rejects BGR textures anyway
but we may want to change this soon. The problem with format
conversion would happen under GLES because that does not support BGR
textures at all so Cogl has to do the conversion. However it doesn't
currently show either because GLES has no support for buffer objects
anyway.

It's also questionable whether the patch would give any performance
benefit because Cairo needs read/write access which implies the buffer
can't be put in write-optimised memory.

Conflicts:

	clutter/clutter-cairo-texture.c

http://bugzilla.openedhand.com/show_bug.cgi?id=1982