6659 nvlist_free(NULL) is a no-op

@@ -1162,11 +1162,10 @@
                  * pending events indefinitely.
                  */
                 mutex_exit(&chp->ch_mutex);
                 evch_dl_del(&eg->evch_list, &chp->ch_link);
                 evch_evq_destroy(chp->ch_queue);
-                if (chp->ch_propnvl)
                         nvlist_free(chp->ch_propnvl);
                 mutex_destroy(&chp->ch_mutex);
                 mutex_destroy(&chp->ch_pubmx);
                 cv_destroy(&chp->ch_pubcv);
                 kmem_free(chp->ch_name, chp->ch_namelen);

@@ -1570,11 +1569,10 @@
 {
         evch_chan_t *chp = bp->bd_channel;
 
         mutex_enter(&chp->ch_mutex);
 
-        if (chp->ch_propnvl)
                 nvlist_free(chp->ch_propnvl);
 
         chp->ch_propnvl = nvl;
         chp->ch_propnvlgen++;