pkt-line: drop safe_write function

This is just write_or_die by another name. The one
distinction is that write_or_die will treat EPIPE specially
by suppressing error messages. That's fine, as we die by
SIGPIPE anyway (and in the off chance that it is disabled,
write_or_die will simulate it).

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

upload-pack.c

@@ -69,7 +69,8 @@ static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
 		xwrite(fd, data, sz);
 		return sz;
 	}
-	return safe_write(fd, data, sz);
+	write_or_die(fd, data, sz);
+	return sz;
 }
 
 static FILE *pack_pipe = NULL;