bgo#625416 - Don't reload the filechooser's folder during a re-map event

bgo#625416 - Don't reload the filechooser's folder during a re-map event

Long ago, before we had file monitoring at the GIO/Glib level, we would
reload the current folder each time a file chooser gets (re)mapped.
This was basically to let the GIMP recycle the same file chooser for all
file/open or file/save operations, instead of creating a new one every time.
In that case, we reloaded the folder with each ::map() event so that the
file chooser would present an up-to-date view of the folder that was being
displayed.  Now, the folder should always be up-to-date as we do
file monitoring all the time.

Signed-off-by: Federico Mena Quintero <federico@novell.com>