Add variable to switch to granular deployment

- Add TASK_BASED_ENGINE variable to be able
to run granular based deployments

Change-Id: I7812424eca2ac300d893001a8d6b5347a9eb1473
Closes-Bug: #1561407

fuelweb_test/models/fuel_web_client.py

@@ -576,6 +576,11 @@ class FuelWebClient(object):
                 nova_quotas = attributes['editable']['common']['nova_quota']
                 nova_quotas['value'] = True
 
+            if not help_data.TASK_BASED_ENGINE:
+                logger.info('Switch to Granular deploy')
+                attributes['editable']['common']['task_deploy']['value'] =\
+                    False
+
             # Updating attributes is needed before updating
             # networking configuration because additional networks
             # may be created by new components like ironic

fuelweb_test/settings.py

@@ -654,3 +654,5 @@ GERRIT_CHANGE_ID = os.environ.get("GERRIT_CHANGE_ID")
 GERRIT_PATCHSET_NUMBER = os.environ.get("GERRIT_PATCHSET_NUMBER")
 
 DOWNLOAD_FACTS = get_var_as_bool("DOWNLOAD_FACTS", False)
+
+TASK_BASED_ENGINE = get_var_as_bool("TASK_BASED_ENGINE", True)