Merge branch 'jk/receive-pack-deadlocks-with-early-failure'

When receive-pack detects error in the pack header it received in
order to decide which of unpack-objects or index-pack to run, it
returned without closing the error stream, which led to a hang
sideband thread.

* jk/receive-pack-deadlocks-with-early-failure:
  receive-pack: close sideband fd on early pack errors

builtin/receive-pack.c

@@ -826,8 +826,11 @@ static const char *unpack(int err_fd)
 			    : 0);
 
 	hdr_err = parse_pack_header(&hdr);
-	if (hdr_err)
+	if (hdr_err) {
+		if (err_fd > 0)
+			close(err_fd);
 		return hdr_err;
+	}
 	snprintf(hdr_arg, sizeof(hdr_arg),
 			"--pack_header=%"PRIu32",%"PRIu32,
 			ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));