module is a variable, not a name prefix

Turns out we want module.exit_json, not module_exit_json. Oops. Also,
two other small ansible task cleanups found looking at the runs.

Change-Id: I8737d5b1e675bfb89ee1db2f2c434c601d419f5e

library/puppet_get_hiera_file_list

@@ -62,7 +62,7 @@ def main():
         if os.path.exists(full_path):
             good_paths.append(full_path)
 
-    module_exit_json(paths=good_paths)
+    module.exit_json(paths=good_paths)
 
 # import module snippets
 from ansible.module_utils.basic import *

tasks/main.yml

@@ -7,7 +7,6 @@
       owner: root
       group: root
       mode: 0700
-    when: copy_hieradata is defined and copy_hieradata
     with_items:
     - fqdn
     - group
@@ -26,12 +25,14 @@
       dest: "{{ item }}"
       mode: 0600
     with_items: hiera_file_paths.paths
+    when: hiera_file_paths is defined
 
   - name: ensure hieradata manifest link is present
     file:
       src: "{{ hieradata }}"
       dest: "{{ manifest_base }}/hieradata"
       state: link
+    when: manifest_base is defined
 
   when: copy_hieradata