Fix checks for presence of old-style 'enabled' key

'iptables:service:enabled' is a key from old version of 'iptables'
formula. New formula relies on the fact that old-style pillar data
is not present.

Testing if 'pillar.iptables.service.enabled' is / is not defined
will fail is 'pillar.iptables.service' is not defined.

This commit fixes the issue by using 'service' data structure
retrieved with defaults values of empty dicts.

Change-Id: I820ead66f6067dd66c9e19f7b748455d8752924c
2 files changed