Allow to deprecate policy

if a policy is marked as 'deprecate = yes' in swift.conf:
    * it will not appear in /info of the cluster
    * upload/download/delete/post are allowed on the existing containers
      with this policy.
    * clients will get error when trying to create container with this policy
    * clients can get the policy info via HEAD on the existing
      containers created with this policy
    * clients also can set new metadata via POST to the containers with
      this policy

corner cases:
    * deprecated policy will ignore the default option
    * deprecating a default policy make the policy with the lowest index default

Change-Id: Ia72d39dca0c993e461e0e8cadef1dc91be98f3f4
Merge "Allow to deprecate policy" into feature/ec