Rubocop fix parentheses around keyword for only_if guards in recipes/default.rb
Rubocop fix parentheses around keyword for only_if guards in recipes/default.rb

Signed-off-by: Michael Kristan <f00431df4a4190bbb820690ba5a95ba9be0f842e@mitre.org>

chef-cookbooks/squid,opscode-cookbooks/squid,opscode-cookbooks/squid,snkutlu/squid,chef-cookbooks/squid,snkutlu/squid