Add secrets operations in cloudify.py

Add secrets operations in cloudify.py

It tries to prevent race conditions when running cloudify_ims.

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/functest/core/singlevm.py", line 411, in run
    if not self.execute():
  File "/usr/lib/python2.7/site-packages/functest/opnfv_tests/vnf/ims/cloudify_ims.py", line 120, in execute
    self.cfy_client.secrets.create(k, val)
  File "/usr/lib/python2.7/site-packages/cloudify_rest_client/secrets.py", line 86, in create
    response = self.api.put('/secrets/{0}'.format(key), data=data)
  File "/usr/lib/python2.7/site-packages/cloudify_rest_client/client.py", line 263, in put
    timeout=timeout)
  File "/usr/lib/python2.7/site-packages/cloudify_rest_client/client.py", line 233, in do_request
    'SSL, but the client does'.format(e)
ConnectionError: ('Connection aborted.', BadStatusLine("''",))

Change-Id: Id2603bbda462b50d3140b6f45894c8810d542e4c
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>