gio: Add some casts for printf() formatting statbufs on Solaris

Apparently Solaris defines statbuf fields as long when Linux doesn’t, in
some cases. Cast down to the type expected by the printf() format
placeholder.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://bugzilla.gnome.org/show_bug.cgi?id=749652

gio/gdbusauthmechanismsha1.c

@@ -273,7 +273,7 @@ ensure_keyring_directory (GError **error)
                            G_IO_ERROR_FAILED,
                            _("Permissions on directory “%s” are malformed. Expected mode 0700, got 0%o"),
                            path,
-                           statbuf.st_mode & 0777);
+                           (guint) (statbuf.st_mode & 0777));
               g_free (path);
               path = NULL;
               goto out;