xl: export 'outstanding_pages' value from xcinfo

xl: export 'outstanding_pages' value from xcinfo

This patch provides the value of the currently outstanding pages
claimed for a specific domain. This is a value that influences
the global outstanding claims value (See patch: "xl: 'xl info'
print outstanding claims if enabled") returned via
xc_domain_get_outstanding_pages hypercall. This domain value
decrements as the memory is populated for the guest and
eventually reaches zero.

With this patch it is possible to utilize this field.

Acked-by: Ian Campbell <ian.campbell@citrix.com>
[v2: s/unclaimed/outstanding/ per Tim's suggestion]
[v3: Don't use SXP printout file per Ian's suggestion]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>