This adds interfaces to the glance plugin for uploading / downloading
vhd files by glance url instead of with a host / port / use_ssl
tuple. This makes it possible to have glance hosted on a non root url
and still work with xenserver.
This bumps the plugin version to 1.3 as these are new functions exposed.
Convert xenapi driver to using up/down vhd2
All unit test converted to use this new functionality.
Change-Id: I73f60de0b1644827238961e1659b0119b80bf82f
89de4ed5e9