Remove WebEngine from mingw and msvc2010 and msvc2012 configurations

WebEngine is compiled only for msvc2013 packages so remove the
WebEngine installer configuration from other Windows packages.

Change-Id: I85bb08d76f50d90829bbd19655007632e7dae23b
Reviewed-by: Jani Heikkinen <jani.heikkinen@digia.com>