Remove a redundant dictionary

There is not an any usage of "resp" dictionary.

Change-Id: I6ed2f2b37e4d38540644fa9d2aa3cc24f62877b3
diff --git a/tempest/api/compute/images/test_images_negative.py b/tempest/api/compute/images/test_images_negative.py
index e91944f..8db094d 100644
--- a/tempest/api/compute/images/test_images_negative.py
+++ b/tempest/api/compute/images/test_images_negative.py
@@ -64,8 +64,6 @@
         # Create a new image with invalid server id
         name = data_utils.rand_name('image')
         meta = {'image_type': 'test'}
-        resp = {}
-        resp['status'] = None
         self.assertRaises(lib_exc.NotFound, self.create_image_from_server,
                           '!@$^&*()', name=name, meta=meta)