Fix beaker on xenial

Since the beaker jobs are being run on xenial, we need a special nodeset
for it, otherwise beaker gives an error:

 beaker-hostgenerator was not able to use this value as input.
 Exiting with an Error.

We also want to install puppet from the Ubuntu repos rather than from
puppetlabs, since puppetlabs doesn't support puppet 3 for Xenial. For
centos we can keep the install process the same.

Change-Id: Ifd2244ae9dd212b2475f9cd6adb994bc058a4769
Depends-On: Ife2993b07dd995fc97676c002a91d0e695407522

spec/acceptance/nodesets/nodepool-xenial.yml

@@ -0,0 +1,10 @@
+HOSTS:
+  ubuntu-16.04-amd64:
+    roles:
+      - master
+    platform: ubuntu-16.04-amd64
+    hypervisor: none
+    ip: 127.0.0.1
+CONFIG:
+  type: foss
+  set_env: false

spec/spec_helper_acceptance.rb

@@ -2,7 +2,14 @@ require 'beaker-rspec'
 
 hosts.each do |host|
 
-  install_puppet
+  # puppet 3 isn't available from apt.puppetlabs.com so install it from the Xenial repos
+  on host, "which apt-get && apt-get install puppet -y", { :acceptable_exit_codes => [0,1] }
+  # otherwise use the beaker helpers to install the yum.puppetlabs.com repo and puppet
+  r = on host, "which yum",  { :acceptable_exit_codes => [0,1] }
+  if r.exit_code == 0
+    install_puppet
+  end
+  add_platform_foss_defaults(host, 'unix')
 
   on host, "mkdir -p #{host['distmoduledir']}"
 end