Merge pull request #50 from robhoes/master

xenopsd: Support driver domains for PV guests
Add RRD interface dependencies

Signed-off-by: John Else <john.else@citrix.com>
Implement registration of rrdd plugins by xenopsd

Signed-off-by: John Else <john.else@citrix.com>
Make /local/domain/<domid>/rrd writeable for guests

Signed-off-by: John Else <john.else@citrix.com>
Add a means of deregistering interdomain RRD plugins

A plugin will be deregistered if it writes "true" to
/local/domain/<domid>/rrd/<plugin-name>/shutdown

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #47 from johnelse/xenostats

Register domU RRD plugins with RRDD
xl: rename timeout function

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>