openstack: fix API doc for delete_floating_ip()
openstack: fix API doc for delete_floating_ip()

Prior to this change, Sphinx would not render the "ip" parameter type
properly.

Add a space so Sphinx will interpret the type properly.

andrewsomething/libcloud,andrewsomething/libcloud,Kami/libcloud,ByteInternet/libcloud,Scalr/libcloud,StackPointCloud/libcloud,apache/libcloud,ByteInternet/libcloud,apache/libcloud,mistio/libcloud,mistio/libcloud,Scalr/libcloud,StackPointCloud/libcloud,mistio/libcloud,StackPointCloud/libcloud,Scalr/libcloud,apache/libcloud,ByteInternet/libcloud,Kami/libcloud,Kami/libcloud,andrewsomething/libcloud