[PYLINT-FLAKE8][addons-vauxoo] Pylint and Flake8 actions over some modules done for version 7

Pylint and Flake8 was a applied to this modules, that are being used by some modules in the oml:

- account_voucher_tax
- hr_expense_replenishment
- hr_expense_replenishment_tax
- invoice_datetime
@jorgenaranjo 
Esto no marca error, porque está dentro de un parentesis.
Tú puedes probar con
```python
def method(var1, 
	var2, var3=None):
	print "var1", var2

method(True
    and False, 
    True
    and False)
```