remote-curl: reencode http error messages

We currently recognize an error message with a content-type
"text/plain; charset=utf-16" as text, but we ignore the
charset parameter entirely. Let's encode it to
log_output_encoding, which is presumably something the
user's terminal can handle.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-httpd/error.sh

@@ -15,6 +15,10 @@ case "$PATH_INFO" in
 	printf "text/plain; charset=utf-8"
 	charset=utf-8
 	;;
+*utf16*)
+	printf "text/plain; charset=utf-16"
+	charset=utf-16
+	;;
 esac
 printf "\n"