No zookeeper packages on CentOS slaves

Change 12c4749a tried to install zookeeper on all Ubuntu and CentOS
unit test slaves, but there is not actually a zookeeper-server
package in CentOS or EPEL. Install only on Ubuntu instead.

Change-Id: Ia50f016ef8d53dada63dd3218c7d731016b94383

modules/jenkins/manifests/params.pp

@@ -51,7 +51,8 @@ class jenkins::params {
       $xslt_package = 'libxslt'
       $xvfb_package = 'xorg-x11-server-Xvfb'
       # For Tooz unit tests
-      $zookeeper_package = 'zookeeper-server'
+      # FIXME: No zookeeper packages on RHEL
+      #$zookeeper_package = 'zookeeper-server'
       $cgroups_package = 'libcgroup'
       if ($::operatingsystem == 'Fedora') {
         $cgroups_tools_package = 'libcgroup-tools'

modules/jenkins/manifests/slave.pp

@@ -62,7 +62,6 @@ class jenkins::slave(
     $::jenkins::params::unzip_package,
     $::jenkins::params::xslt_package, # for building openstack docs
     $::jenkins::params::xvfb_package, # for selenium tests
-    $::jenkins::params::zookeeper_package, # for tooz unit tests
   ]
 
   if ($bare == false) {
@@ -113,6 +112,11 @@ class jenkins::slave(
         require => Package[$::jenkins::params::jdk_package],
       }
 
+      # For Tooz unit tests
+      package { $::jenkins::params::zookeeper_package:
+        ensure => present,
+      }
+
     }
     default: {
       fail("Unsupported osfamily: ${::osfamily} The 'jenkins' module only supports osfamily Debian or RedHat (slaves only).")