Use server's timezone for defaults (#1484288)

config/main.inc.php.dist

@@ -226,10 +226,10 @@ $rcmail_config['include_host_config'] = FALSE;
 $rcmail_config['pagesize'] = 40;
 
 // use this timezone to display date/time
-$rcmail_config['timezone'] = 1;
+$rcmail_config['timezone'] = intval(date('O'))/100 - date('I');
 
-// daylight savings are On
-$rcmail_config['dst_active'] = TRUE;
+// if daylight savings are On
+$rcmail_config['dst_active'] = (bool)date('I');
 
 // prefer displaying HTML messages
 $rcmail_config['prefer_html'] = TRUE;