Docs for behaviour change of drop database during Hot Standby

Adding missing docs for previous Hot Standby patch.

doc/src/sgml/backup.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.133 2009/12/20 03:49:58 rhaas Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.134 2010/01/10 16:27:27 sriggs Exp $ -->
 
 <chapter id="backup">
  <title>Backup and Restore</title>
@@ -2169,7 +2169,8 @@ if (!triggered)
        </listitem>
        <listitem>
         <para>
-         Dropping databases on the primary while that role is connected on standby.
+         Dropping databases on the primary while users are connected to that
+         database on the standby.
         </para>
        </listitem>
        <listitem>
@@ -2542,7 +2543,8 @@ LOG:  database system is ready to accept read only connections
     Running <command>DROP DATABASE</>, <command>ALTER DATABASE ... SET TABLESPACE</>,
     or <command>ALTER DATABASE ... RENAME</> on primary will generate a log message
     that will cause all users connected to that database on the standby to be
-    forcibly disconnected, once <varname>max_standby_delay</> has been reached.
+    forcibly disconnected. This action occurs immediately, whatever the setting of
+	<varname>max_standby_delay</>.
    </para>
 
    <para>