test(inspec): enable use_upstream_repo for debian & centos-6

* Add new `centos-6` image
* Install `9.6` from upstream repo

test/integration/default/controls/services_spec.rb

@@ -1,8 +1,14 @@
+# Overide by OS
+service_name = 'postgresql'
+if os[:name] == 'centos' and os[:release].start_with?('6')
+  service_name = 'postgresql-9.6'
+end
+
 control 'Postgres service' do
   impact 0.5
   title 'should be running and enabled'
 
-  describe service('postgresql') do
+  describe service(service_name) do
     it { should be_enabled }
     it { should be_running }
   end

test/salt/pillar/postgres.sls

@@ -5,15 +5,19 @@ postgres.port: '5432'
 postgres:
   # UPSTREAM REPO
   # Set True to configure upstream postgresql.org repository for YUM/APT/ZYPP
+  {%- if not (grains.os_family == 'Debian' or grains.osfinger == 'CentOS-6') %}
   use_upstream_repo: False
-  # # Version to install from upstream repository (if upstream_repo: True)
-  # version: '10'
+  {%- else %}
+  use_upstream_repo: True
+  # Version to install from upstream repository (if upstream_repo: True)
+  version: '9.6'
   # # Set True to add a file in /etc/profile.d adding the bin dir in $PATH
   # # as packages from upstream put them somewhere like /usr/pgsql-10/bin
   # add_profile: False
   # # If automatic package installation fails, use `fromrepo` to specify the
   # # upstream repo to install packages from [#133, #185] (if upstream_repo: True)
   # fromrepo: 'jessie-pgdg'
+  {%- endif %}
 
   # ### MACOS
   # # Set to 'postgresapp' OR 'homebrew' for MacOS