Revert "Dynamic GL support in Quick1's ShaderEffectSource"

Will need to change to QOpenGLContext::currentContext()->isES()
once the qtbase changes are in.

This reverts commit 3eeaf987123f73ad7a4745745d9e7c70f30942cd.

Change-Id: I7ac8718bc07cbcbaefe1633856722ae402078112
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>