QmlDesigner.nodeInstances: improving warnings if building qmlpuppet fails

Change-Id: I7dfecd8e0ad0016748ef4513cf0364e8dcd7d121
Reviewed-on: http://codereview.qt.nokia.com/715

Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@nokia.com>

share/qtcreator/qml/qmlpuppet/qmlpuppet.pro

@@ -6,8 +6,8 @@ exists($${QT_PRIVATE_HEADERS}/QtDeclarative/private/qdeclarativecontext_p.h) {
     minQtVersion(4, 7, 1) {
         SUBDIRS += qmlpuppet
     } else {
-        warning(Qt 4.7.1 required!)
+        warning(Qt version has to be at least 4.7.1 to build qmlpuppet.)
     }
 } else {
-    warning(No private headers in Qt!)
+    warning(Private headers for Qt required to build qmlpuppet.)
 }