Set master hostname in puppet.conf during install

Adds another ini_setting resource to create an [agent] block in
/etc/puppet/puppet.conf and set the puppet master hostname to the
current hostname.  This will only be activated on build-server roles
and the all_in_one scenario.  Without this it's necessary to specify
the puppet master hostname each time puppet agent is run.

Change-Id: Ic6832ebec44e198e26b3b3553b315ead8e93feb5
Closes-Bug: 1285307

manifests/setup.pp

@@ -96,6 +96,15 @@ if $::puppet_run_mode != 'agent' {
     value   => 'scenario',
     require => Package['puppet'],
   }
+
+  ini_setting {'puppetmastername':
+    ensure  => present,
+    path    => '/etc/puppet/puppet.conf',
+    section => 'agent',
+    setting => 'server',
+    value   => "${::hostname}.${::build_server_domain_name}",
+    require => Package['puppet'],
+  }
 }
 
 # Lay down a file that can be used for subsequent runs to puppet. Often, the