wordpress 4.1 upgrade database problem

I found a different solution to not being able to access the dashboard after the automatic upgrade preventing from accessing 15 sites!
on checking the path:
wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F

I went to my wp-admin folder via ftp and saw that upgrade.php file
was actually named _upgrade.php So I removed the underscore and it allowed the databae update to be completed and everything worked fine.
This was true for all 15 of my sites.