[kwin] Reparse shared configuration before reconfiguring an Effect

When the Effect has to be reconfigured the configuration most likely
changed, thus we should reload it. Of course it would be possible to also
do this in each Effect::reconfigureEffect, but this would mean that the
configuration would be reloaded during startup, which we do not want.

effects.cpp

@@ -1656,6 +1656,8 @@ void EffectsHandlerImpl::reconfigureEffect(const QString& name)
 {
     for (QVector< EffectPair >::const_iterator it = loaded_effects.constBegin(); it != loaded_effects.constEnd(); ++it)
         if ((*it).first == name) {
+            KSharedConfig::Ptr config = KSharedConfig::openConfig(QStringLiteral(KWIN_CONFIG));
+            config->reparseConfiguration();
             makeOpenGLContextCurrent();
             (*it).second->reconfigure(Effect::ReconfigureAll);
             return;