Python 3 fixes.

moto/glacier/responses.py

@@ -123,7 +123,7 @@ class GlacierResponse(_TemplateEnvironmentMixin):
                 "Marker": None,
             })
         elif method == 'POST':
-            json_body = json.loads(body)
+            json_body = json.loads(body.decode("utf-8"))
             archive_id = json_body['ArchiveId']
             job_id = self.backend.initiate_job(vault_name, archive_id)
             headers['x-amz-job-id'] = job_id

tests/test_glacier/test_glacier_archives.py

@@ -10,7 +10,7 @@ from moto import mock_glacier
 @mock_glacier
 def test_create_and_delete_archive():
     the_file = NamedTemporaryFile(delete=False)
-    the_file.write("some stuff")
+    the_file.write(b"some stuff")
     the_file.close()
 
     conn = boto.glacier.connect_to_region("us-west-2")