Remove unused test-requirments
Remove unused test-requirments

WebOb is not needed in our test code.
So remove it to make less dependences.

Change-Id: I4910263449ff3d49c4ee44a6ef7a7762875fe76f

dtroyer/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient,dtroyer/python-openstackclient