QmlJS: Only try qmldump on Desktop and Simulator Qt.

In particular, don't complain about a missing qmldump binary on other
platforms.

Change-Id: Ie2e96bcb67e609aa5aed31510b06139d2d9ce77e
Reviewed-on: http://codereview.qt-project.org/5327
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Leandro T. C. Melo <leandro.melo@nokia.com>

src/libs/qmljs/qmljsmodelmanagerinterface.h

@@ -61,6 +61,7 @@ public:
     {
     public:
         ProjectInfo()
+            : tryQmlDump(false)
         { }
 
         ProjectInfo(QPointer<ProjectExplorer::Project> project)
@@ -80,8 +81,12 @@ public:
         QPointer<ProjectExplorer::Project> project;
         QStringList sourceFiles;
         QStringList importPaths;
+
+        // whether trying to run qmldump makes sense
+        bool tryQmlDump;
         QString qmlDumpPath;
         Utils::Environment qmlDumpEnvironment;
+
         QString qtImportsPath;
         QString qtVersionString;
     };