Fixed the upgrade from 1.6.x. The role->shortname field was not being created.

lib/db/mysql.php

@@ -2005,6 +2005,7 @@ function main_upgrade($oldversion=0) {
         execute_sql("CREATE TABLE {$CFG->prefix}role (
                               `id` int(10) unsigned NOT NULL auto_increment,
                               `name` varchar(255) NOT NULL default '',
+                              `shortname` varchar(100) NOT NULL default '',
                               `description` text NOT NULL default '',
                               `sortorder` int(10) unsigned NOT NULL default '0',
                               PRIMARY KEY  (`id`)

lib/db/postgres7.php

@@ -1622,6 +1622,7 @@ function main_upgrade($oldversion=0) {
          modify_database('', "CREATE TABLE prefix_role (
                                   id SERIAL PRIMARY KEY,
                                   name varchar(255) NOT NULL default '',
+                                  shortname varchar(100) NOT NULL default '',     
                                   description text NOT NULL default '',
                                   sortorder integer NOT NULL default '0'
                                 );");