> Empty Go strings should be converted to `nil` libxl_cpuid_policy_list;
> otherwise libxl_cpuid_parse_config gets confused.
>
> Also, libxl_cpuid_policy_list returns a weird error, not a "normal"
> libxl error; if it returns one of these non-standard errors, convert
> it to ErrorInval.
>
>
Empty Go strings should be converted to `nil` libxl_cpuid_policy_list;
otherwise libxl_cpuid_parse_config gets confused.
Also, libxl_cpuid_policy_list returns a weird error, not a "normal"
libxl error; if it returns one of these non-standard errors, convert
it to ErrorInval.
Signed-off-by:
