sendmail mode quoting bug fix.

lisp/ChangeLog

 2012-03-10  Richard Stallman  <rms@gnu.org>
 
+	* mail/sendmail.el (mail-encode-header):
+	Set rfc2047-encode-encoded-words.
+
 	* mail/mail-utils.el (mail-quote-printable): Quote multibyte chars.
 
 	* mail/rmail.el (rmail-buffers-swapped-p): Don't assume dead

lisp/mail/sendmail.el

@@ -1085,7 +1085,9 @@ Return non-nil if and only if some part of the header is encoded."
 		(cons selected mm-coding-system-priorities)
 	      mm-coding-system-priorities))
 	   (tick (buffer-chars-modified-tick))
-	   (rfc2047-encode-encoded-words nil))
+	   ;; rms: this proved necessary, but I don't recall why.
+	   ;; Can anyone determine why, and state it here?
+	   (rfc2047-encode-encoded-words t))
       (rfc2047-encode-message-header)
       (= tick (buffer-chars-modified-tick)))))