Do not set displayName in BaseQtVersion

This will trigger a run of qmake -query which depends on a virtual
method. Set the display name in the derived Qt versions instead.

Change-Id: I47380fd25d38a2cf748a26e9c8324f3b23cb3b39
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qnx/qnxqtversion.cpp

@@ -46,6 +46,7 @@ QnxQtVersion::QnxQtVersion()
 QnxQtVersion::QnxQtVersion(QnxArchitecture arch, const Utils::FileName &path, bool isAutoDetected, const QString &autoDetectionSource)
     : QnxAbstractQtVersion(arch, path, isAutoDetected, autoDetectionSource)
 {
+    setDisplayName(defaultDisplayName(qtVersionString(), path, false));
 }
 
 QnxQtVersion *QnxQtVersion::clone() const