client/server: request ETA instead of having the server send it automatically

Also changes the 'serial' of the command to a tag, that's passed
back and forth for commands that need to use it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.h b/stat.h
index 68bc970..b564ebf 100644
--- a/stat.h
+++ b/stat.h
@@ -190,7 +190,7 @@
 
 extern void show_thread_status(struct thread_stat *ts, struct group_run_stats *rs);
 extern void show_group_stats(struct group_run_stats *rs);
-extern int calc_thread_status(struct jobs_eta *je);
+extern int calc_thread_status(struct jobs_eta *je, int force);
 extern void display_thread_status(struct jobs_eta *je);
 
 #endif