TIMEOUT(absolute) returned negative value.

(closes issue #15513)
Reported by: ys



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@206877 65c4cc65-6c06-0410-ace0-fbb531ad65f3

funcs/func_timeout.c

@@ -90,7 +90,7 @@ static int timeout_read(struct ast_channel *chan, const char *cmd, char *data,
 			ast_copy_string(buf, "0", len);
 		} else {
 			myt = ast_tvnow();
-			snprintf(buf, len, "%.3f", ast_tvdiff_ms(myt, chan->whentohangup) / 1000.0);
+			snprintf(buf, len, "%.3f", ast_tvdiff_ms(chan->whentohangup, myt) / 1000.0);
 		}
 		break;