This function is used to return the memory needed for a guest. It's not
in a position to modify the b_info passed in (note the _setdefault
function).
Constify the passed in b_info, use a copy to do the calculation. Mark
the change in API in libxl.h.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>