xenlight: LIBXL_SHUTDOWN_REASON_UNKNOWN is now 255

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
xenlight: update to xen 4.3

NOTE: the #define OCAML_READY lines need to be put back in!

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
b2bmerge (trunk-ring3 to trunk) needed some help.
Merge commit '14215939b7970f153c27524f674908f937f1d2e9'

Conflicts were in these autogenerated files:
	xenlight/xenlight.ml
	xenlight/xenlight.mli
	xenlight/xenlight_stubs.c

Resolved by just taking the trunk-ring3 versions.