Code review comment for ~sylvain-pineau/checkbox-support:fix-1467521

Ha! I cannot add inline comments below on lines 5k+ :D
So here they go:

Stylistic comment:
Instead of those 4 cascaded ifs I'd rather have:

if '/dev/mapper' in self._environment.get('DEVLINKS', ''):
    if self._environment.get('ID_FS_TYPE') != 'swap':

# note the elegant None != 'swap' or 'some_string' != 'swap' resulting from the get()

The code's still good, +0.99