tests: Ensure XXE injection tests have config loaded

Depending on test order (and possibly whether there were earlier
failures?) the new tests may trip KeyErrors when trying to get
s3_access_key values. Solution seems to be defining
setUpModule() / tearDownModule() like other functional tests.

Also fix up some Content-MD5 handling; if we're using pre-signed URLs,
we can't provide a Content-MD5.

Change-Id: Ifce72ec255b1b618b9914ce5785d04ee0ebd3b8c
Related-Change: I84494123cfc85e234098c554ecd3e77981f8a096
(cherry picked from commit 3550e00dd9)

test/functional/s3api/test_xxe_injection.py

@@ -14,17 +14,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import base64
 import requests
 
 import botocore
 
-from swift.common.utils import md5
-
 import test.functional as tf
 from test.functional.s3api import S3ApiBaseBoto3
 
 
+def setUpModule():
+    tf.setup_package()
+
+
+def tearDownModule():
+    tf.teardown_package()
+
+
 class TestS3ApiXxeInjection(S3ApiBaseBoto3):
 
     def setUp(self):
@@ -144,11 +149,8 @@ class TestS3ApiXxeInjection(S3ApiBaseBoto3):
 </Delete>
 """
         body = body.encode('utf-8')
-        content_md5 = (
-            base64.b64encode(md5(body, usedforsecurity=False).digest()))
-        resp = requests.post(
-            url, headers={'Content-MD5': content_md5}, data=body)
-        self.assertEqual(400, resp.status_code)
+        resp = requests.post(url, data=body)
+        self.assertEqual(400, resp.status_code, resp.content)
         self.assertNotIn(b'xxe', resp.content)
         self.assertNotIn(b'[swift-hash]', resp.content)