glocalfile: Remove redundant private header

There are glocalfile.h and glocalfileprivate.h header files currently.
None of those header files is public, so it doesn't make sense to have
two private headers for glocalfile.c. Let's remove glocalfileprivate.h.

gio/glocalfile.h

@@ -51,6 +51,8 @@ gboolean g_local_file_is_remote (const gchar *filename);
 GFile * g_local_file_new_from_dirname_and_basename (const char *dirname,
                                                     const char *basename);
 
+gchar *_g_local_file_find_topdir_for (const char *file_path);
+
 G_END_DECLS
 
 #endif /* __G_LOCAL_FILE_H__ */