(maint) Fix PuppetDB Accp Tests

Prior to this commit, there were some extra comments that needed to be
removed, a variable had extra quotes/interpolation, and some
if-statements needed to use is_pe? to check if the host is Puppet
  Enterprise. This commit fixes those issues.
(maint) Change main to master

Prior to this commit, all of the with_puppet_running_on functions passed
its config to main. This commit changes it so they all use master
instead of main.
(maint) Fix json diff check and Helper Fix

Prior to this commit, the function munge_resource_for_comparison did not
properly convert the edges data into a set for comparison. It also add
redundant code within install_postgresql for pe hosts. This commit
fixes that check within the function and also simplifies the code within
install_postgresql.