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

@@ -1,10 +1,11 @@
 <?xml version="1.0"?>
 <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1">
 <!--
  Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  Copyright 2016 Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
+ Copyright 2019 Joyent, Inc.
 
  CDDL HEADER START
 
  The contents of this file are subject to the terms of the
  Common Development and Distribution License (the "License").

@@ -100,11 +101,11 @@
                         </prop_pattern>
                         <prop_pattern name='single_instance' type='boolean'
                             required='false'>
                                 <description>
                                         <loctext xml:lang='C'>
-Only one instance of this service may be run.  This property is currently unenforced, but will be at some point in the future.
+Only one instance of this service may be run.  This behavior is unimplemented, and obsolete.
                                         </loctext>
                                 </description>
                                 <cardinality min='1' max='1'/>
                         </prop_pattern>
                 </pg_pattern>