[Master] Remove vim modelines and resulting trailing blank lines.

See discussions at https://github.com/odoo/odoo/pull/4174

PR generated with
```bash
grep -i -r -l -e '# \?vim:' --include="*.py" | xargs sed -i -e '/# \?vim:/d'
find . -name "*.py" -print | xargs sed -i ':1;/^\n*$/{$d;N;b1}'
```