perf hists: Initialize all of he->stat with zeroes

Not just nr_events and period.
Reported-by: Namhyung Kim <namhyung@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-8nodd6b4bytyf1snf96oy531@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/hist.c

@@ -742,8 +742,7 @@ static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
 
 	he = hist_entry__new(pair);
 	if (he) {
-		he->stat.nr_events = 0;
-		he->stat.period    = 0;
+		memset(&he->stat, 0, sizeof(he->stat));
 		he->hists = hists;
 		rb_link_node(&he->rb_node, parent, p);
 		rb_insert_color(&he->rb_node, &hists->entries);