Improve public and private IP address handling in OpenStack 1.1 driver. Assume
every IP address which doesn't have a label "public" or "internet" is private.

Part of LIBCLOUD-297.


git-svn-id: https://svn.apache.org/repos/asf/libcloud/trunk@1447256 13f79535-47bb-0310-9956-ffa450edef68