old_contents: """
  Commands from HTTP Server (from manager_queue):
      Run the test to the next break:
          {
          'session': '1a2b4f3c'
          'cmd':'run',
          'break': --- see break requests for tank
          'test': --- only when creating new session
          'config': --- only when creating new  session
          }
      Stop the test
          {
          'session': '1a2b4f3c'
          'cmd':'stop'
          }
  
  
  Status reported by tank (from manager_queue):
      {
       'session': '1a2b4f3c'
       'test': 'DEATHSTAR-10-12345'
       'status': 'running'|'success'|'failure'
       'current_stage': --- current stage (from test_stage_order)
       'break': --- stage to make a break before
       'failures': --- [ {'stage': stage-at-which-failed,'reason': reason of failure },
                         {'stage':stage-of-next-failure,'reason':...},
                         ... ]
       }
  =====
  
  Break requests (into tank_queue):
      {'break': --- any stage from test_stage_order }
  
  ====
  Status reported to HTTP Server (into webserver_queue):
      {
      'session': '1a2b4f3c'
      'test': 'DEATHSTAR-10-12345'
      'status': 'running'|'success'|'failed' (from tank or from  manager)
                 running: the tank is running
                 success: tank has exited and no failures occured
                 failed: tank has exited and there were failures
  
      'stage': --- optional, from tank only. This is the last stage that was executed.
      'break': --- optional, from tank only. The next break.
      'reason' : --- optional (from manager)
      'failures': --- optional, from tank only
      }
  """
  
  test_stage_order = ['lock', 'init', 'configure', 'prepare',
                      'start', 'poll', 'end', 'postprocess', 'unlock', 'finished']
  
  
  def is_A_earlier_than_B(stage_A, stage_B):
      """Slow but reliable"""
      return test_stage_order.index(stage_A) < test_stage_order.index(stage_B)
  
  
  def get_valid_breaks():
      return test_stage_order
  
  
  def is_valid_break(brk):
      return brk in test_stage_order
  
new_contents: """
  Commands from HTTP Server (from manager_queue):
      Run the test to the next break:
          {
          'session': '1a2b4f3c'
          'cmd':'run',
          'break': --- see break requests for tank
          'test': --- only when creating new session
          'config': --- only when creating new  session
          }
      Stop the test
          {
          'session': '1a2b4f3c'
          'cmd':'stop'
          }
  
  
  Status reported by tank (from manager_queue):
      {
       'session': '1a2b4f3c'
       'test': 'DEATHSTAR-10-12345'
       'status': 'running'|'success'|'failure'
       'current_stage': --- current stage (from test_stage_order)
       'break': --- stage to make a break before
       'failures': --- [ {'stage': stage-at-which-failed,'reason': reason of failure },
                         {'stage':stage-of-next-failure,'reason':...},
                         ... ]
       }
  =====
  
  Break requests (into tank_queue):
      {'break': --- any stage from test_stage_order }
  
  ====
  Status reported to HTTP Server (into webserver_queue):
      {
      'session': '1a2b4f3c'
      'test': 'DEATHSTAR-10-12345'
      'status': 'running'|'success'|'failed' (from tank or from  manager)
                 running: the tank is running
                 success: tank has exited and no failures occured
                 failed: tank has exited and there were failures
  
      'stage': --- optional, from tank only. This is the last stage that was executed.
      'break': --- optional, from tank only. The next break.
      'reason' : --- optional (from manager)
      'failures': --- optional, from tank only
      }
  """
  
  test_stage_order = ['init','lock', 'configure', 'prepare',
                      'start', 'poll', 'end', 'postprocess', 'unlock', 'finished']
  
  
  def is_A_earlier_than_B(stage_A, stage_B):
      """Slow but reliable"""
      return test_stage_order.index(stage_A) < test_stage_order.index(stage_B)
  
  
  def get_valid_breaks():
      return test_stage_order
  
  
  def is_valid_break(brk):
      return brk in test_stage_order
  
subject: change stage order: fix stage order checks