Initial commit of XenAPI provider - non-functional skeleton
This is the first commit of code for the XenAPI provider. Most of it is ripped-off (or inspired by) the ec2 provider structure. Currently the provider doesn't do much, but there is code for interacting with XCP hosts through the XenAPI, and 'juju bootstrap' will actually create a VM on the target pool.
Signed-off-by: Mike McClurg <mike.mcclurg@gmail.com>