[PATCH] bug 145237: parent-folders button does not look like a button

[Michael Henson <mike axl net>]

I had brought this up a while back, but no progress came of it. Seeing
as there has not been any better solution would it be ok to get this
added? It is such a small change, but I think it would really help
people to identify that area actually having a purpose other than
displaying the directory name. 

If the icon is still deemed a waste of space I can remove it, but I do
think it helps give a better indication that the button will allow you
to open another folder than just the bevel alone.

-- Michael