Coverity reports leak-on-BUG() in rend_client_get_random_intro_impl()

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*** CID 1455168:  Resource leaks  (RESOURCE_LEAK)
/src/feature/rend/rendclient.c: 1061 in rend_client_get_random_intro_impl()
1055       usable_nodes = smartlist_new();
1056       smartlist_add_all(usable_nodes, entry->parsed->intro_nodes);
1057     
1058       /* Get service ID so we can use it to query the failure cache. If we fail to
1059        * parse it, this cache entry is no good. */
1060       if (BUG(rend_get_service_id(entry->parsed->pk, service_id) < 0)) {
>>>     CID 1455168:  Resource leaks  (RESOURCE_LEAK)
>>>     Variable "usable_nodes" going out of scope leaks the storage it points to.
1061         return NULL;
1062       }
1063     
1064       /* Remove the intro points that have timed out during this HS
1065        * connection attempt from our list of usable nodes. */
1066       SMARTLIST_FOREACH_BEGIN(usable_nodes, const rend_intro_point_t *, ip) {