perf tools: Free the terms list_head in parse_events__free_terms()

perf tools: Free the terms list_head in parse_events__free_terms()

Fixing a leak, since code calling parse_events__free_terms() expect it
to free the list_head too.

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 ]
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>