Add support for locking and unlocking servers

Partially implements: blueprint lock-unlock-server

Change-Id: I6d261cc7fb314bda60f0732f7a7bb3b23ba7c179
Merge "Add support for locking and unlocking servers"
Fixes ceilometer test data spelling error:

 * Modified 'intance' to 'instance' in resource
   data

Change-Id: I8def4292d9e8bfd99c4f136d2c8255a5c0ee010f
Closes-Bug: #1392170