Fixed python-barbicanclient functional tests.
Fixed python-barbicanclient functional tests.

When using KMIP backend, some barbican client functional
tests failed in payload length validation. Fixed the test case
payload data.

Change-Id: I9d0b2d04662b3a7399603b9eff20d9daf406e069
Closes-Bug: #1570166

openstack/python-barbicanclient