perf metric: Fix memory leaks

Certain error paths may leak memory as caught by address sanitizer.
Ensure this is cleaned up to make sure address/leak sanitizer is happy.

Fixes: 5ecd5a0c7d1cca79 ("perf metrics: Modify setup and deduplication")
Signed-off-by: Ian Rogers <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/metricgroup.c

···
 	free(m->metric_refs);
 	expr__ctx_free(m->pctx);
 	free((char *)m->modifier);
+	evlist__delete(m->evlist);
 	free(m);
 }
 
···
 	}
 
 
-	if (combined_evlist)
+	if (combined_evlist) {
 		evlist__splice_list_tail(perf_evlist, &combined_evlist->core.entries);
+		evlist__delete(combined_evlist);
+	}
 
 	list_for_each_entry(m, &metric_list, nd) {
 		if (m->evlist)