CBQE-0: fix hunging jenkins job

error
Exception in thread Cluster_Thread:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "lib/tasks/taskmanager.py", line 31, in run
    task.step(self)
  File "lib/tasks/task.py", line 58, in step
    self.check(task_manager)
  File "lib/tasks/task.py", line 397, in check
    if len(rest.get_pools_info()["pools"]) == 0:
KeyError: 'pools'

Change-Id: I9caeadc75801211c20084b0b0289934aff188b63
Reviewed-on: http://review.couchbase.org/41744
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>