sideband: mark "remote error:" prefix for translation

A Git client may produce a "remote error:" message (along with whatever
error the other side sent us) in two places:

  - when we see an ERR packet

  - when we're using a sideband and see sideband 3

We can't reliably translate the message the other side sent us, but we
can do so for our own prefix. However, we translate only the ERR-packet
case but not the sideband-3 case. Let's make them consistent (by marking
both for translation).

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

sideband.c

@@ -147,7 +147,7 @@ int demultiplex_sideband(const char *me, char *buf, int len,
 	switch (band) {
 	case 3:
 		if (die_on_error)
-			die("remote error: %s", buf + 1);
+			die(_("remote error: %s"), buf + 1);
 		strbuf_addf(scratch, "%s%s", scratch->len ? "\n" : "",
 			    DISPLAY_PREFIX);
 		maybe_colorize_sideband(scratch, buf + 1, len);