perf evlist: Use the right prefix for 'struct evlist' methods: evlist__set_leader()

perf_evlist__ is for 'struct perf_evlist' methods, in tools/lib/perf/,
go on completing this split.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index ae8edde..3d3b465 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -1089,7 +1089,7 @@ static PyObject *pyrf_evlist__open(struct pyrf_evlist *pevlist,
 		return NULL;
 
 	if (group)
-		perf_evlist__set_leader(evlist);
+		evlist__set_leader(evlist);
 
 	if (evlist__open(evlist) < 0) {
 		PyErr_SetFromErrno(PyExc_OSError);