(maint) fix update node pp

[seamymckenna]

Summary

Fix for the below issue

puppetlabs/comply-demo % bundle exec bolt -i ./spec/fixtures/litmus_inventory.yaml --native-ssh task run provision::update_node_pp --targets bodily-pitcher.delivery.puppetlabs.net target_node=bodily-pitcher.delivery.puppetlabs.net manifest=test

Started on bodily-pitcher.delivery.puppetlabs.net...
Failed on bodily-pitcher.delivery.puppetlabs.net:
  The task failed with exit code 1 and no stdout, but stderr contained:
  /tmp/2db07819-a48a-475a-9ec6-9efaa81f79f8/update_node_pp.rb:12: syntax error, unexpected '}'
  ...r: ' %{stderr}')" % { stderr: }) if status != 0
  ...                              ^
Failed on 1 target: bodily-pitcher.delivery.puppetlabs.net
Ran on 1 target in 15.09 sec

line getting exercised as status now returns value like "pid 27325 exit 0" as its string representation.
We should use success? method instead