QmlProfiler: Make range selection boundaries consistent

You shouldn't be able to select out of range areas with the selector in
the timeline if you can't scroll to see them anyway.

Change-Id: Ia1909f463db2c64dc2605eac7f4be53a76222338
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/plugins/qmlprofiler/qml/SelectionRange.qml

@@ -69,6 +69,11 @@ RangeMover {
     }
 
     function setPos(pos) {
+        if (pos < 0)
+            pos = 0;
+        else if (pos > width)
+            pos = width;
+
         switch (creationState) {
         case 1: {
             setLeft(pos);