[impr-OpenMage#101] Only use base url for homepage in generated sitem…

…ap.xml

tja. works for 99% is important to have right for 100%. But this solution is not sound proof.
Still I would advise to accept it. As de base-url is always the homepage ... and I am not sure
we would want to create another config option with "use baseurl als main homepage yes/no"

app/code/core/Mage/Sitemap/Model/Sitemap.php

@@ -197,13 +197,16 @@ public function generateXml()
         /**
          * Generate cms pages sitemap
          */
+        $homepage = (string)Mage::getStoreConfig('web/default/cms_home_page', $storeId);
         $changefreq = (string)Mage::getStoreConfig('sitemap/page/changefreq', $storeId);
         $priority   = (string)Mage::getStoreConfig('sitemap/page/priority', $storeId);
         $collection = Mage::getResourceModel('sitemap/cms_page')->getCollection($storeId);
         foreach ($collection as $item) {
+            $url = $item->getUrl();
+            if ( $url == $homepage) { $url = ''; }
             $xml = sprintf(
                 '<url><loc>%s</loc><lastmod>%s</lastmod><changefreq>%s</changefreq><priority>%.1f</priority></url>',
-                htmlspecialchars($baseUrl . $item->getUrl()),
+                htmlspecialchars($baseUrl . $url),
                 $date,
                 $changefreq,
                 $priority