xenctrl.0.9.26: add depext for xenserver

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #38 from djs55/add-xenserver

xenctrl.0.9.26: add depext for xenserver
rrdd-plugin doesn't need obuild any more

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #39 from johnelse/rrdd-plugin-no-obuild

rrdd-plugin doesn't need obuild any more