Add missing timeout when calling entity with timeout (#1311)

I found this issue while working on a Robottelo upgrade scenario
refactor. I found that a test syncing the RHEL 7 server RPMs repo was
consistently timing out after 300 seconds, though the
`enable_sync_redhat_repo` API factory method uses a timeout of 1500
seconds by default. Eventually, I found that
`nailgun.entity_mixins.call_entity_with_timeout()` was invoking the
entity callable without specifically passing the timeout. After the repo
sync was initiated, `nailgun.entity_mixins._poll_task()` was being
called with no timeout value specified, causing the `timeout` variable
to be set to the `TASK_TIMEOUT` constant defined in the entity_mixins
module, which has a value of 300 seconds. My repo sync was completing in
~360 seconds, so the test was consistently failing.

This PR adds a `timeout` keyword argument to the `entity_callable()` in
`call_entity_with_timeout()` and, in the repository `sync()` entity
method, changes the `timeout` argument in the call to
`_handle_response()` from a keywork argument to a positional argument.

(cherry picked from commit 62bee40)

Author: synkd

nailgun/entities.py

@@ -6305,7 +6305,7 @@ def sync(self, synchronous=True, timeout=None, **kwargs):
         kwargs = kwargs.copy()  # shadow the passed-in kwargs
         kwargs.update(self._server_config.get_client_kwargs())
         response = client.post(self.path('sync'), **kwargs)
-        return _handle_response(response, self._server_config, synchronous, timeout)
+        return _handle_response(response, self._server_config, synchronous, timeout=timeout)
 
 
 class ProductBulkAction(Entity):

nailgun/entity_mixins.py

@@ -73,7 +73,7 @@ def call_entity_method_with_timeout(entity_callable, timeout=300, **kwargs):
     original_task_timeout = TASK_TIMEOUT
     TASK_TIMEOUT = timeout
     try:
-        entity_callable(**kwargs)
+        entity_callable(timeout=timeout, **kwargs)
     finally:
         TASK_TIMEOUT = original_task_timeout