Expose number of shared pages through libxl.

Signed-off-by: Adin Scannell <adin@scannell.ca>

diff -r 28e1a8b6c934 -r 2a5e57e2a3d2 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -337,6 +337,7 @@ static void xcinfo2xlinfo(const xc_domai
         xlinfo->shutdown_reason  = ~0;

     xlinfo->current_memkb = PAGE_TO_MEMKB(xcinfo->tot_pages);
+    xlinfo->shared_memkb = PAGE_TO_MEMKB(xcinfo->shr_pages);
     xlinfo->max_memkb = PAGE_TO_MEMKB(xcinfo->max_pages);
     xlinfo->cpu_time = xcinfo->cpu_time;
     xlinfo->vcpu_max_id = xcinfo->max_vcpu_id;
diff -r 28e1a8b6c934 -r 2a5e57e2a3d2 tools/libxl/libxl.idl
--- a/tools/libxl/libxl.idl
+++ b/tools/libxl/libxl.idl
@@ -40,6 +40,7 @@ libxl_dominfo = Struct("dominfo",[
 Otherwise set to a value guaranteed not to clash with any valid
 SHUTDOWN_* constant."""),
     ("current_memkb",   uint64),
+    ("shared_memkb", uint64),
     ("max_memkb",   uint64),
     ("cpu_time",    uint64),
     ("vcpu_max_id", uint32),