filechooser: Do not look up parents of directories

filechooser: Do not look up parents of directories

If the `GtkRecentInfo` represents a directory, simply use it, and
do not try to find its parent in `_gtk_file_chooser_extract_recent_folders()`.

For example, there is an entry in my recently-used database
from the Amberol music player about the folder I have opened
with it, but the folder is not listed on the "Recent" tab of
the file chooser widget, only its parent. After this change,
the directory itself is shown.