Add ca_certificates_file option to test against SSL servers

tempest has an option to ignore SSL errors
(disable_ssl_certificate_validation) but no way to pass in
a CA bundle to be used to do actual validation. This new option,
ca_certificates_file, will provide this bundle.

boto testing will be handled separately as it gets CA
certificates from its configuration file.

This is configured in either /etc/boto.cfg or the file pointed
to by $BOTO_CONFIG via:

[Boto]
ca_certificates_file = /path/to/ca-bundle.pem

Change-Id: I5662e881f7d71ed34a8fe4b9d0a2541a6ff1bad3
Closes-bug: #1395754
diff --git a/tempest/scenario/test_swift_basic_ops.py b/tempest/scenario/test_swift_basic_ops.py
index fcb9505..312fbc6 100644
--- a/tempest/scenario/test_swift_basic_ops.py
+++ b/tempest/scenario/test_swift_basic_ops.py
@@ -65,7 +65,10 @@
         obj_name, _ = self.upload_object_to_container(container_name)
         obj_url = '%s/%s/%s' % (self.object_client.base_url,
                                 container_name, obj_name)
-        http_client = http.ClosingHttp()
+        dscv = CONF.identity.disable_ssl_certificate_validation
+        ca_certs = CONF.identity.ca_certificates_file
+        http_client = http.ClosingHttp(
+            disable_ssl_certificate_validation=dscv, ca_certs=ca_certs)
         resp, _ = http_client.request(obj_url, 'GET')
         self.assertEqual(resp.status, 401)
         self.change_container_acl(container_name, '.r:*')