JsonWizard: Remove homebrew QValue(bool).toString()

QValue(bool).toString() does return "true":"false".

Change-Id: I01021eeb6be8a6e65b2fdd61c5adfee1766dbf31
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/projectexplorer/jsonwizard/jsonwizard.cpp

@@ -127,9 +127,6 @@ QString JsonWizard::stringValue(const QString &n) const
     if (!v.isValid())
         return QString();
 
-    if (v.type() == QVariant::Bool)
-        return v.toBool() ? QString::fromLatin1("true") : QString::fromLatin1("false");
-
     if (v.type() == QVariant::String) {
         QString tmp = m_expander.expand(v.toString());
         if (tmp.isEmpty())