Install requirements repo on slaves

In advance of starting to use the requirements project as the basis
for doing mirror selection, ensure that the repo is installed on all
of the jenkins slaves.

Change-Id: I893dd82e759f6a84a62400cdcbc7596b19ec5923

modules/jenkins/manifests/slave.pp

@@ -306,6 +306,13 @@ class jenkins::slave(
     mode   => '0440',
   }
 
+  vcsrepo { '/opt/requirements':
+    ensure   => latest,
+    provider => git,
+    revision => 'master',
+    source   => 'https://git.openstack.org/openstack/requirements',
+  }
+
   # Temporary for debugging glance launch problem
   # https://lists.launchpad.net/openstack/msg13381.html
   # NOTE(dprince): ubuntu only as RHEL6 doesn't have sysctl.d yet