Install openstacksdk on zuul executors

For use in uploading logs to swift.

Change-Id: I1302d960951b9358cd5d4c878194e9ad68036076

manifests/executor.pp

@@ -51,6 +51,13 @@ class zuul::executor (
     require => Class['::pip::python3'],
   }
 
+  # openstacksdk is used by the swift role in zuul-jobs
+  package { 'openstacksdk':
+    ensure   => latest,
+    provider => 'pip3',
+    require  => Class['pip'],
+  }
+
   if ($::operatingsystem == 'Ubuntu') and ($::operatingsystemrelease >= '16.04') {
     # This is a hack to make sure that systemd is aware of the new service
     # before we attempt to start it.