perf tools: Unlink entries from terms list

We were just freeing them, better unlink and init its nodes to catch
bugs faster if we keep dangling references to them.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
[ Spun off from another patch, use list_del_init() instead of list_del() ]
Link: http://lkml.kernel.org/r/1454680939-24963-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -2072,8 +2072,10 @@ void parse_events__free_terms(struct list_head *terms)
 {
 	struct parse_events_term *term, *h;
 
-	list_for_each_entry_safe(term, h, terms, list)
+	list_for_each_entry_safe(term, h, terms, list) {
+		list_del_init(&term->list);
 		free(term);
+	}
 }
 
 void parse_events_evlist_error(struct parse_events_evlist *data,