Really convert to multibyte in Fdirectory_append

* src/fileio.c (Fdirectory_append): Fix check for whether we need
to convert to multibyte.
(Fdirectory_append):

1 files changed, 1 insertions, 2 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 60f5650302c..6d505fd0f01 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -799,8 +799,7 @@ usage: (record DIRECTORY &rest COMPONENTS) */)
           if (STRING_MULTIBYTE (arg) || string_ascii_p (arg))
             elements[i] = arg;
           else
-            elements[i] = make_multibyte_string (SSDATA (arg), SCHARS (arg),
-                                                 SCHARS (arg));
+            elements[i] = Fstring_to_multibyte (arg);
           arg = elements[i];
           /* We have to recompute the number of bytes. */
           if (i == nargs - 1