resolve remaining flake8 issues

Author: Gabriel Monroy

api/models.py

@@ -436,7 +436,7 @@ def converge(self, databag):
     def destroy(self):
         # create subtasks to terminate all nodes in parallel
         all_layers = self.layer_set.all()
-        tasks = [ layer.destroy(async=True) for layer in all_layers ]
+        tasks = [layer.destroy(async=True) for layer in all_layers]
         node_tasks, layer_tasks = [], []
         for n, l in tasks:
             node_tasks.extend(n), layer_tasks.extend(l)
@@ -491,12 +491,12 @@ def build(self, *args, **kwargs):
     def destroy(self, async=False):
         tasks = import_tasks(self.flavor.provider.type)
         # create subtasks to terminate all nodes in parallel
-        node_tasks = [ node.destroy(async=True) for node in self.node_set.all() ]
+        node_tasks = [node.destroy(async=True) for node in self.node_set.all()]
         # purge other hosting provider infrastructure
         name = "{0}-{1}".format(self.formation.id, self.id)
         args = (name, self.flavor.provider.creds.copy(),
                 self.flavor.params.copy())
-        layer_tasks = [ tasks.destroy_layer.subtask(args) ]
+        layer_tasks = [tasks.destroy_layer.subtask(args)]
         if async:
             return node_tasks, layer_tasks
         # destroy nodes, then the layer

api/tests/layer.py

@@ -161,7 +161,7 @@ def test_layer_scale(self):
 
     def test_layer_scale_no_creds(self):
         url = '/api/providers/autotest'
-        body = {'creds': json.dumps({}) }
+        body = {'creds': json.dumps({})}
         response = self.client.patch(url, json.dumps(body), content_type='application/json')
         self.assertEqual(response.status_code, 200)
         # try to scale and a formation