Fix for pki_setup

pki_setup works only if keystone-user and keystone-group are
provided

Change-Id: I58c10e0cf39792d3096e3c3e4c0fa37ba40de2b1
Closes-Bug: 1561586

manifests/init.pp

@@ -794,6 +794,7 @@ class keystone(
     }
 
     exec { 'keystone-manage pki_setup':
+      command     => "keystone-manage pki_setup --keystone-user ${keystone_user} --keystone-group ${keystone_group}",
       path        => '/usr/bin',
       refreshonly => true,
       creates     => $signing_keyfile,

spec/classes/keystone_spec.rb

@@ -356,6 +356,7 @@ describe 'keystone' do
       end
 
       it { is_expected.to contain_exec('keystone-manage pki_setup').with(
+        :command => 'keystone-manage pki_setup --keystone-user keystone --keystone-group keystone',
         :creates => '/etc/keystone/ssl/private/signing_key.pem'
       ) }
       it { is_expected.to contain_file('/var/cache/keystone').with_ensure('directory') }