Examples: Update open file tooltip

And fix one import QtQuick 2.0 -> QtQuick 2.1

Change-Id: If22ef7c4c47923f4cd84c1c8c232c10c79b110e7
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

examples/gallery/content/ImageViewer.qml

@@ -37,7 +37,7 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-import QtQuick 2.0
+import QtQuick 2.1
 import QtQuick.Window 2.1
 
 Window {

examples/gallery/main.qml

@@ -100,7 +100,7 @@ ApplicationWindow {
             shortcut: "Ctrl+O"
             iconSource: "images/document-open.png"
             onTriggered: fileDialog.open()
-            tooltip: "(Pretend to) open a file"
+            tooltip: "open an image"
         }
 
         Action {