curzone reality check and teardown changes to use the RIGHT zone

*** 2565,2575 ****
  nlm_unexport(struct exportinfo *exi)
  {
          struct nlm_globals *g;
          struct nlm_host *hostp;
  
!         g = zone_getspecific(nlm_zone_key, curzone);
  
          mutex_enter(&g->lock);
          hostp = avl_first(&g->nlm_hosts_tree);
          while (hostp != NULL) {
                  struct nlm_vhold *nvp;
--- 2565,2581 ----
  nlm_unexport(struct exportinfo *exi)
  {
          struct nlm_globals *g;
          struct nlm_host *hostp;
  
!         /* This may be called on behalf of global-zone doing shutdown. */
!         ASSERT(exi->exi_zone == curzone || curzone == global_zone);
!         g = zone_getspecific(nlm_zone_key, exi->exi_zone);
!         if (g == NULL) {
!                 /* Did zone cleanup get here already? */
!                 return;
!         }
  
          mutex_enter(&g->lock);
          hostp = avl_first(&g->nlm_hosts_tree);
          while (hostp != NULL) {
                  struct nlm_vhold *nvp;