use null for db/database config, check for it

lib/default.php

@@ -66,7 +66,7 @@ $default =
               'minify' => true, // true to use the minified versions of JS files; false to use orig files. Can aid during development
               ),
         'db' =>
-        array('database' => 'YOU HAVE TO SET THIS IN config.php',
+          array('database' => null, // must be set
               'schema_location' => INSTALLDIR . '/classes',
               'class_location' => INSTALLDIR . '/classes',
               'require_prefix' => 'classes/',

lib/statusnet.php

@@ -383,6 +383,7 @@ class StatusNet
                 $config['cache']['base'] = $config['memcached']['base'];
             }
         }
+
         if (array_key_exists('xmpp', $config)) {
             if ($config['xmpp']['enabled']) {
                 addPlugin('xmpp', array(
@@ -398,6 +399,12 @@ class StatusNet
                 ));
             }
         }
+
+        // Check for database server; must exist!
+
+        if (empty($config['db']['database'])) {
+            throw new ServerException("No database server for this site.");
+        }
     }
 
     /**