libxl: initialise cpupoolinfo in libxl__domain_scheduler

If libxl_cpupool_info fails then we would call
libxl_cpupoolinfo_dispose on an uninitialised struct, and possibly
free an invalid pointer.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

tools/libxl/libxl_dom.c

@@ -81,6 +81,7 @@ libxl_scheduler libxl__domain_scheduler(libxl__gc *gc, uint32_t domid)
     if (cpupool < 0)
         return sched;
 
+    libxl_cpupoolinfo_init(&poolinfo);
     rc = libxl_cpupool_info(CTX, &poolinfo, cpupool);
     if (rc < 0)
         goto out;