JSON wizards: Print parsing issues only with -customwizard-verbose

Some wizards will miss required components when corresponding plugins
are disabled. That is fine, and not an error per se. When actually
developing a wizard, these kind of errors should of course be posted,
but that is what -customwizard-verbose is for.

Fixes: QTCREATORBUG-28502
Change-Id: I3647d37ef7ca4dace7592c5443bdd13720290016
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/projectexplorer/jsonwizard/jsonwizardfactory.cpp

@@ -480,6 +480,7 @@ JsonWizardFactory *JsonWizardFactory::createWizardFactory(const QVariantMap &dat
     if (!factory->initialize(data, baseDir, errorMessage)) {
         delete factory;
         factory = nullptr;
+        if (verbose())
             Core::MessageManager::writeDisrupting(*errorMessage);
     }
     return factory;