v.out.postgis: fix postgis topology link

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@62798 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.out.postgis/v.out.postgis.html

@@ -265,7 +265,7 @@ page</a>.
 
 <ul>
   <li><a href="http://www.opengeospatial.org/standards/sfa">OGC Simple Feature Access</a> specification</li>
-  <li><a href="http://postgis.refractions.net/docs/Topology.html">PostGIS Topology</a> documentation</li>
+  <li><a href="http://postgis.net/docs/Topology.html">PostGIS Topology</a> documentation</li>
   <li><a href="http://grass.osgeo.org/programming7/vlibPg.html">GRASS-PostGIS data provider</a></li>
 </ul>