api-ref: re-work resize action post-conditions
api-ref: re-work resize action post-conditions

This change does a few things:

1. Moves the post-condition paragraph into an
   "Asynchronous Postconditions" section like other
   API references.

2. Drops the "RESIZED" VM status wording since what
   that probably meant was the server OS-EXT-STS:vm_state
   value would be "resized" but what was in the reference
   was (a) wrong and (b) redundant with the VERIFY_RESIZE
   status.

3. Re-words and links the resize_confirm_window config
   option wording since saying "if you set" a config option
   in the API reference does not really make sense since
   "you" (the non-admin cloud user) does not have control
   over how the cloud is configured.

Change-Id: I77830dfb738cd78c830dc3ce7ea88216c1eac7ef

klmitch/nova,mahak/nova,klmitch/nova,klmitch/nova,mahak/nova,mahak/nova,openstack/nova,klmitch/nova,rahulunair/nova,rahulunair/nova,openstack/nova,rahulunair/nova,openstack/nova