Fix several rubocop errors.

Deleted extra blank space, used 2 spaces instead of 3, use parens
instead of curly braces

attributes/default.rb

@@ -113,7 +113,6 @@ end
 # Master.cf attributes
 default['postfix']['master']['submission'] = false
 
-
 # OS Aliases
 case node['platform']
 when 'freebsd'

recipes/_common.rb

@@ -110,7 +110,7 @@ unless node['postfix']['smtp_generic_map_entries'].empty?
   end
 end
 
-%w{main master}.each do |cfg|
+%w( main master ).each do |cfg|
   template "#{node['postfix']['conf_dir']}/#{cfg}.cf" do
     source "#{cfg}.cf.erb"
     owner 'root'