Removing dos end of line

Hi,

  I am trying to rewrite a git history and remove dos end of line. I used:

git filter-branch --tree-filter dos2unix -- --all

However it still report:

error: You have local changes to 'bla.c'; cannot switch branches.

Here is my setting:

$ cat ~/.gitconfig
...
[core]
	autocrlf = input


Should I be doing something else to remove dos file from history ?

Thanks,
-- 
Mathieu