html.tpl.php is deleted and the site is down!
Found a solution. An unconventional solution though!


Step I: I moved my custom theme from sites/all/themes/ to one step up (sites/all/). So the system cannot identify the theme in place. I got access into the Drupal.
Step II: I set "Bartik 7.22" as the Default theme.
Step III: Then moved my theme back to its place again.
Step IV: Renamed the file html.tpl.php to html.tpl.php.BACKUP.
Step V: Then reactivated and set default my theme in the Appearance.


It's live!


  Reason: I think it's the Drupal cache. The process I followed was simply tweaking the caching in an alternative, but unconventional way.