completely remove a file from a git repository

i committed  site path configuration file into git repository in my drupal module. After some commit only i created the gitignore  file and add  path configuration file into gitignore. I have to remove that configuration file from my  previous commit also. To do that just to :

$ git filter-branch --tree-filter 'rm -f my_file' HEAD

Reference: http://stackoverflow.com/questions/3458685/how-can-i-completely-remove-a-file-from-a-git-repository

thanks