filetype on before filetype off, for git&svn comment editing.

When using vimified, vim may exit with code 1 after :wq.
Usually, it is not a big problem.
But when using vim to write git/svn commit message, it always failed for the exit code of vim.
After a lot of checking and googling, it turns out that vim will exit with 1 when .vimrc setup 'filetype off' before turn on filetype switch.
So, turn it on first and then turn it off.
Everything is fine now.