Rename the param controller_node_address

    The param controller_node_address in openstack::swift::proxy is
    puzzling, b/c it actually means the keystone host address,but the
    keystone_host is not always equivalent to controller_host.
    This patch rename it to the keystone_host.

Change-Id: Ia58d256370b3fa94c9f1010245f6a20395b668f1