hv_xen: Test various forms of getting instance/node info
hv_xen: Test various forms of getting instance/node info

Test functions for retrieving instance and node information.

Signed-off-by: Michael Hanselmann <68b67885ff74281219b4a4be33cc20fd45078d7c@google.com>
Reviewed-by: Helga Velroyen <2d0126b1ec6f9ec5cbec4a7012aa14faeaef10f5@google.com>

mbakke/ganeti,dimara/ganeti,yiannist/ganeti,ganeti/ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,grnet/snf-ganeti,andir/ganeti,ganeti/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti,ganeti/ganeti,bitemyapp/ganeti,andir/ganeti,onponomarev/ganeti,andir/ganeti,grnet/snf-ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,dimara/ganeti,bitemyapp/ganeti,onponomarev/ganeti,leshchevds/ganeti,leshchevds/ganeti,yiannist/ganeti