Add parser = future config option to puppet.conf

Enable testing puppet 3 with the future parser[1] by adding the boolean
parameter 'futureparser' to the role, which will turn on `parser =
future` in puppet.conf if set.

[1] https://docs.puppet.com/puppet/3.8/experiments_future.html

Change-Id: Ia65948ba954457d873758ed08502e844151f5cf5

defaults/main.yml

@@ -16,3 +16,4 @@ puppet_hiera_datadir: '/opt/system-config/'
 puppet_environment_basedir: '/opt/system-config/'
 puppet_environment: production
 puppet_timeout: 30m
+futureparser: False

templates/puppet.conf.j2

@@ -15,6 +15,9 @@ basemodulepath = {{ puppet_basemodulepath }}
 {% if puppet_environmentpath != '' %}
 environmentpath={{ puppet_environmentpath }}
 {% endif %}
+{% if puppet_version != '4' and futureparser == True %}
+parser = future
+{% endif %}
 
 [master]
 # These are needed when the puppetmaster is run by passenger