Fix error where barbican order create returns invalid error
Fix error where barbican order create returns invalid error

When performing barbican order create we obtain the error that:
'NoneType' object has no attribute 'lower'. This patch fixes that.
Closes-Bug: #1481996

Change-Id: If09c72eae731e40b6055ba8ef062b0cd4536e48a

openstack/python-barbicanclient