Merge pull request #1750 from tkolhar/test_cli

Added test for user - role add and remove
Make EntityDeleteMixin.delete deal with HTTP 204s

An HTTP 204 response indicates that a request has been processed but no content
is being returned. When this happens, any attempt to decode the JSON in a
response will fail, because no content is available to decode that content. Make
`EntityDeleteMixin.delete` deal with this case. This fixes a test failure.
Updated test results:

    $ nosetests tests/foreman/api/test_multiple_paths.py:DoubleCheckTestCase -m 1_ActivationKey
    .S.
    ----------------------------------------------------------------------
    Ran 3 tests in 31.344s

    OK (SKIP=1)
Drop unused method Organization.fetch_rhproduct_id

Before change:

    $ git grep fetch_rhproduct_id
    robottelo/api/utils.py:    prd_id = entities.Product().fetch_rhproduct_id(name=product, org_id=org_id)
    robottelo/entities.py:    def fetch_rhproduct_id(self, name):
    robottelo/entities.py:    def fetch_rhproduct_id(self, name, org_id):

After change:

    $ git grep fetch_rhproduct_id
    robottelo/api/utils.py:    prd_id = entities.Product().fetch_rhproduct_id(name=product, org_id=org_id)
    robottelo/entities.py:    def fetch_rhproduct_id(self, name, org_id):
Merge pull request #1751 from Ichimonji10/delete-204

Make EntityDeleteMixin.delete deal with HTTP 204s
Merge pull request #1752 from Ichimonji10/unused-method

Drop unused method Organization.fetch_rhproduct_id