Fix authorized_key module crashing when given an invalid key

I tried a playbook with the following (accidentally wrong) task:

  tasks:
      - name: authorized key test
        authorized_key: key=/home/sam/.ssh/id_rsa.pub key_options='command="/foo/bar"' user=sam

I got the following traceback:

    TASK: [authorized key test] ***************************************************
    failed: [localhost] => {"failed": true, "parsed": false}
    Traceback (most recent call last):
    File "/home/sam/.ansible/tmp/ansible-tmp-1427110003.65-277897441194582/authorized_key", line 2515, in <module>
        main()
    File "/home/sam/.ansible/tmp/ansible-tmp-1427110003.65-277897441194582/authorized_key", line 460, in main
        results = enforce_state(module, module.params)
    File "/home/sam/.ansible/tmp/ansible-tmp-1427110003.65-277897441194582/authorized_key", line 385, in enforce_state
        parsed_new_key = (parsed_new_key[0], parsed_new_key[1], parsed_options, parsed_new_key[3])
    TypeError: 'NoneType' object has no attribute '__getitem__'

With this fix, I see the expected error instead:

    TASK: [authorized key test] ***************************************************
    failed: [localhost] => {"failed": true}
    msg: invalid key specified: /home/sam/.ssh/id_rsa.pub

lib/ansible/modules/system/authorized_key.py

@@ -377,13 +377,14 @@ def enforce_state(module, params):
     # Check our new keys, if any of them exist we'll continue.
     for new_key in key:
         parsed_new_key = parsekey(module, new_key)
-        if key_options is not None:
-            parsed_options = parseoptions(module, key_options)
-            parsed_new_key = (parsed_new_key[0], parsed_new_key[1], parsed_options, parsed_new_key[3])
 
         if not parsed_new_key:
             module.fail_json(msg="invalid key specified: %s" % new_key)
 
+        if key_options is not None:
+            parsed_options = parseoptions(module, key_options)
+            parsed_new_key = (parsed_new_key[0], parsed_new_key[1], parsed_options, parsed_new_key[3])
+
         present = False
         matched = False
         non_matching_keys = []