Fix kwin build with GLES

Review Request #104558 - Created April 12, 2012 and submitted - Latest diff uploaded

Michael Palimaka
buildsystem, kwin
When compiling kwin with GLES and without OpenGL, build fails because some parts do not realise that GLES is being used. This is because of KWIN_HAVE_OPENGLES_COMPOSITING being previously removed in 026e0f418d27466a6fe855bbe95a50ea5dd71b4b and some references being missed.

This patch switches the conditional to OPENGLES_FOUND, so that -DKWIN_HAVE_OPENGLES is again passed to the build disabling OpenGL-only features.
Builds with OpenGL on & GLES off, OpenGL off & GLES on, and both OpenGL & GLES on complete as expected. In each case, the appropriate OpenGL or GLES-specific libraries were built.