Move /xapi/* -> /xenops/* in XenStore

It's really xenops that's using these paths so it makes sense that these paths
be under that name.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #1496 from simonjbeaumont/xenops-xenstore-paths

Move /xapi/* -> /xenops/* in XenStore