Support ERR in remote archive like in fetch/push

Make ERR as first packet of remote snapshot reply work like it does in
fetch/push. Lets servers decline remote snapshot with message the same
way as declining fetch/push with a message.

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/archive.c

@@ -49,6 +49,8 @@ static int run_remote_archiver(int argc, const char **argv,
 	if (strcmp(buf, "ACK")) {
 		if (len > 5 && !prefixcmp(buf, "NACK "))
 			die(_("git archive: NACK %s"), buf + 5);
+		if (len > 4 && !prefixcmp(buf, "ERR "))
+			die(_("remote error: %s"), buf + 4);
 		die(_("git archive: protocol error"));
 	}