(maint) Use correct providers to install gems

Prior to this commit, the test setup was using the same gem
provider for PE and FOSS and all versions. Correct this so that
it using the correct provider with certain versions of puppet and
PE.

spec/spec_helper_acceptance.rb

@@ -5,7 +5,18 @@
 unless ENV['RS_PROVISION'] == 'no'
   run_puppet_install_helper
   hosts.each do |host|
-    on host, puppet('resource package hocon provider=puppet_gem')
+    puppet_version = (on default, puppet('--version')).output.chomp
+
+    if ENV['PUPPET_INSTALL_TYPE'] == 'pe'
+      if Gem::Version.new(puppet_version) < Gem::Version.new('4.0.0')
+        on host, puppet('resource package hocon provider=pe_gem')
+      else
+        on host, puppet('resource package hocon provider=puppet_gem')
+      end
+    else
+      on host, puppet('resource package rubygems')
+      on host, puppet('resource package hocon provider=gem')
+    end
   end
 end