corrected indentation and now handles non existing previous key (not

just changed existing)

Signed-off-by: Brian Coca <briancoca+dev@gmail.com>

system/debconf

@@ -146,8 +146,12 @@ def main():
             rc, msg, e = set_selection(module, pkg, question, type, value, unseen)
             if rc:
                 module.fail_json(msg=e)
+
         curr = { question: value }
+        if question in prev:
             prev = {question: prev[question]}
+        else:
+            prev[question] = ''
 
         module.exit_json(changed=changed, msg=msg, current=curr, previous=prev)