- avoid unnecessary string conversion.

Partial cherry pick from: 35f536ddb27633e8cac40eb4c99c5b370fdb14cb

Signed-off-by: Luke Dashjr <luke-jr+git@utopios.org>
(cherry picked from commit 86d107daed)

tdeioslave/imap4/rfcdecoder.cc

@@ -591,7 +591,7 @@ rfcDecoder::encodeRFC2231String (const TQString & _str)
   }
   if (!*l) {
     free(latin);
-    return _str.ascii ();
+    return _str;
   }
   TQCString result;
   l = latin;