Changing default value string to boolean. (#1669)

When downloading containers or files, use boolean
as a default value.

roles/download/defaults/main.yml

@@ -278,15 +278,15 @@ downloads:
     sha256: "{{ tiller_digest_checksum|default(None) }}"
 
 download:
-  container: "{{ file.container|default('false') }}"
+  container: "{{ file.container|default(false) }}"
   repo: "{{ file.repo|default(None) }}"
   tag: "{{ file.tag|default(None) }}"
-  enabled: "{{ file.enabled|default('true') }}"
+  enabled: "{{ file.enabled|default(true) }}"
   dest: "{{ file.dest|default(None) }}"
   version: "{{ file.version|default(None) }}"
   sha256: "{{ file.sha256|default(None) }}"
   source_url: "{{ file.source_url|default(None) }}"
   url: "{{ file.url|default(None) }}"
-  unarchive: "{{ file.unarchive|default('false') }}"
+  unarchive: "{{ file.unarchive|default(false) }}"
   owner: "{{ file.owner|default('kube') }}"
   mode: "{{ file.mode|default(None) }}"