Test Case to check "swift object expiry"

Adds object expiry test case to "test_object_expiry.py" so as to
validate the object expiry support by trying to GET object after
expiry time.

Implements: blueprint add-swift-object-expiry-test
Change-Id: I1a29e8ae57e9f8661c21000775153bda78b0c689
1 file changed