Add example showing how to remove a password from a role.

Andreas Scherbaum

doc/src/sgml/ref/alter_role.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/alter_role.sgml,v 1.9 2007/09/03 18:46:29 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/alter_role.sgml,v 1.10 2008/04/30 12:38:49 alvherre Exp $
 PostgreSQL documentation
 -->
 
@@ -217,6 +217,14 @@ ALTER ROLE davide WITH PASSWORD 'hu8jmn3';
 </programlisting>
   </para>
 
+  <para>
+   Remove a role's password:
+
+<programlisting>
+ALTER ROLE davide WITH PASSWORD NULL;
+</programlisting>
+  </para>
+
   <para>
    Change a password expiration date, specifying that the password
    should expire at midday on 4th May 2015 using