perf python: Init perf_event_attr::size in perf.evsel constructor

Currently 0 is passed as perf_event_attr::size, which could block usage
of new features.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1468148882-10362-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/python.c

@@ -653,6 +653,7 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
 	attr.precise_ip	    = precise_ip;
 	attr.mmap_data	    = mmap_data;
 	attr.sample_id_all  = sample_id_all;
+	attr.size	    = sizeof(attr);
 
 	perf_evsel__init(&pevsel->evsel, &attr, idx);
 	return 0;