6698013: JFileChooser can no longer navigate non-local file systems.
Summary: ShellFolder is used only if possible
Reviewed-by: peterz
<html>
<body>
<applet code="bug6698013.class" width=200 height=200></applet>
1. Go into 'subdir' folder via double click
2. Return to parent directory
3. Go into 'subdir' folder: select 'subdir' folder and press the 'Open' button
</body>
</html>