Fix: Guard now a simple grep

The Ruby guard (as well as containing a typo) will return true
because an empty array (as the result of the select) will still
evaluate to true, so the guard will always take effect.

Replaced with a simple grep -q.
Fix: Set fail2ban attributes at higher precedence

The attributes if set at default will be evaluated in order, meaning
that the one from efg wins, and only ssh is set.  By setting the
fail2ban attributes at normal rather than default we can let Chef merge
do its magic.