Remove positional args to create_server
Remove positional args to create_server

There's no good compelling reason to have them, and it just makes other
places ugly and harder to use.

Change-Id: I0c137c55d7f5b76f343d09f26abe926b2c44b147

openstack/python-openstacksdk,stackforge/python-openstacksdk,openstack-infra/shade,jsmartin/shade,dtroyer/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,jsmartin/shade,openstack/python-openstacksdk,openstack-infra/shade