changed filename 'dir' tags

["Teta Bilianou" <tetonio gmail com>]

I just noticed that in some occasions (eg.
en_US/Installer.xml:210(para)), the tag <filename> is used for the
/etc directory, whereas in the past it used to be <filename
class=\"directory\">.

Which one is the appropriate? Should we update it in our translations
or should we leave it as is because it will change back in the future?

Regards,
Teta