QmlProfiler: disable navigation buttons when no data

Change-Id: Ieee8a4c45919c4598d86a817e3489bd3e519d1c8
Reviewed-on: http://codereview.qt.nokia.com/1181
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Aurindam Jana <aurindam.jana@nokia.com>

src/plugins/qmlprofiler/qml/MainView.js

@@ -36,7 +36,6 @@
 var values = [ ];   //events
 var ranges = [ ];
 var frameFps = [ ];
-var valuesdone = false;
 var xmargin = 0;
 var ymargin = 0;
 var drawFpsGraph = false;
@@ -55,7 +54,6 @@ function reset()
     frameFps = [];
     xmargin = 0;
     ymargin = 0;
-    valuesdone = false;
     nestingDepth = [];
 }