[SF#840]Prefer GLib edit name over display name for path location entry.

There is no reason for path entry to contain "(invalid encoding)" string since
it will prevent that path from being used, it will produce an error always.
Fix path completion listing for display names in paths.

Since display name may be different from filesystem name, we should use
a FmPath from display path to create GFile for listing children, not directly
create a GFile from display path - it may be invalid one so we get no listing.