GSettings migration: factor out dir handling
GSettings migration: factor out dir handling

Move the code that handles iterating over all the files in the
conversion directory out of the main function and into its own.

hyperair/gconf-gdbus,hyperair/gconf-gdbus,GNOME/gconf,GNOME/gconf,GNOME/gconf,GNOME/gconf,hyperair/gconf-gdbus,hyperair/gconf-gdbus