QmlProfiler: correctly displaying status when recording disabled

QmlProfiler: correctly displaying status when recording disabled

Each time a new profiling session is started, the root component
is reloaded.  If Plotter.ranges contains data, which might be
the case when not recording, the count in the root item should
not be reset to 0, and the dataAvailable flag stay to true.

Change-Id: I2a34e30a4ae7179d3675b62792dcae7b9eba0462
Reviewed-on: http://codereview.qt.nokia.com/2118
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>