Heat integration tests failing against https endpoints

Provide ca_file option to pass the ca certificate to verify https
connection. Also pass verify parameter to the test cases which
directly call requests library methods.

Change-Id: I4a81047136d6a64b151180e95c254edea8165349
Closes-Bug: #1553898
diff --git a/functional/test_notifications.py b/functional/test_notifications.py
index 3b8e003..924ef0c 100644
--- a/functional/test_notifications.py
+++ b/functional/test_notifications.py
@@ -179,12 +179,12 @@
                                 callbacks=[handler.process_message],
                                 auto_declare=False):
 
-            requests.post(scale_up_url)
+            requests.post(scale_up_url, verify=self.verify_cert)
             test.call_until_true(20, 0, self.consume_events, handler, 2)
             notifications += handler.notifications
 
             handler.clear()
-            requests.post(scale_down_url)
+            requests.post(scale_down_url, verify=self.verify_cert)
             test.call_until_true(20, 0, self.consume_events, handler, 2)
             notifications += handler.notifications