12071 clarify implementation of single_instance in SMF services
Reviewed by: Robert Mustacchi <rm@fingolfin.org>

*** 21,30 ****
--- 21,31 ----
  /*
   * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
   */
  /*
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+  * Copyright 2019 Joyent, Inc.
   */
  
  
  /*
   * XML document manipulation routines
*** 3315,3327 ****
          }
  
          return (0);
  }
  
! /* ARGSUSED1 */
  static int
! lxml_get_single_instance(entity_t *entity, xmlNodePtr si)
  {
          pgroup_t *pg;
          property_t *p;
          int r;
  
--- 3316,3331 ----
          }
  
          return (0);
  }
  
! /*
!  * Unimplemented and obsolete, but we still process it for compatibility
!  * purposes.
!  */
  static int
! lxml_get_single_instance(entity_t *entity, xmlNodePtr si __unused)
  {
          pgroup_t *pg;
          property_t *p;
          int r;