Include jsonschema only once in requirements
Include jsonschema only once in requirements

Including it in both requirements.txt and test-requirements.txt
gives "Double requirement given" error when rebuilding venv.

Change-Id: I612117f736c15d71864235050e46175bcd775fc8

NaohiroTamura/python-ironicclient,openstack/python-ironicclient,NaohiroTamura/python-ironicclient,openstack/python-ironicclient