Fix "mutable" object as default value

This patch fix the coding issue where "mutable" objects like list, dict
are being used as default value of param.

Current functions with mutable object as default value can create issues
if they will be called in more random order.
For example - first call with non default value and then with default
value. In this case original default will be overridden by the first
function call (as mutable object keep their state among function calls).

This commit also add the hacking check for the same and its
corresponding test.

Closes-Bug: #1330322

Change-Id: I251b316ef6d37f4b95c5e8d73a20a39005c22870
diff --git a/tempest/api/orchestration/base.py b/tempest/api/orchestration/base.py
index d0fb825..0b22de5 100644
--- a/tempest/api/orchestration/base.py
+++ b/tempest/api/orchestration/base.py
@@ -64,8 +64,10 @@
         return admin_client
 
     @classmethod
-    def create_stack(cls, stack_name, template_data, parameters={},
+    def create_stack(cls, stack_name, template_data, parameters=None,
                      environment=None, files=None):
+        if parameters is None:
+            parameters = {}
         resp, body = cls.client.create_stack(
             stack_name,
             template=template_data,