perf hists: Collapse expanded callchains after filter is applied

When a filter is applied a hist entry checks whether its callchain was
folded and account it to the output stat.  But this is rather hacky
and only TUI-specific.  Simply fold the callchains for the entry looks
like a simpler and more generic solution IMHO.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1398327843-31845-6-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

tools/perf/util/hist.c

@@ -716,8 +716,8 @@ static void hists__remove_entry_filter(struct hists *hists, struct hist_entry *h
 	if (h->filtered)
 		return;
 
-	if (h->ms.unfolded)
-		hists->nr_non_filtered_entries += h->nr_rows;
+	/* force fold unfiltered entry for simplicity */
+	h->ms.unfolded = false;
 	h->row_offset = 0;
 
 	hists->stats.nr_non_filtered_samples += h->stat.nr_events;