PIVOT-932: Setting root directory of a file browser that points to a non-default
drive (on Windows) leaves the display inconsistent:  the correct directory is
displayed but the file list is from the root of that drive.

So, suppress changing the root directory when a different drive is selected
while setting the root directory.

This is a merge of revision 1551768 from branches/2.0.x to trunk.


git-svn-id: https://svn.apache.org/repos/asf/pivot/trunk@1551771 13f79535-47bb-0310-9956-ffa450edef68