libxl: set domain scheduling parameters while creating the domU

libxl: set domain scheduling parameters while creating the domU

the domain specific scheduling parameters like cpu_weight, cap, slice, ...
will be set during creating the domain, so this parameters can be defined
in the domain config file

[ Improved the documentation wording slightly. -iwj ]

Signed-off-by: Dieter Bloms <dieter@bloms.de>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>