xl: Do not leak events when a domain exits.

The goto in both of these places misses the event free which would
normally clean up.

==8655== 80 bytes in 1 blocks are definitely lost in loss record 1 of 1
==8655==    at 0x4024370: calloc (vg_replace_malloc.c:593)
==8655==    by 0x406EAAE: libxl__zalloc (libxl_internal.c:83)
==8655==    by 0x4078173: libxl__event_new (libxl_event.c:1167)
==8655==    by 0x4056373: domain_death_occurred (libxl.c:958)
==8655==    by 0x4058D06: domain_death_xswatch_callback (libxl.c:1038)
==8655==    by 0x4078EB5: watchfd_callback (libxl_event.c:458)
==8655==    by 0x407839E: afterpoll_internal (libxl_event.c:949)
==8655==    by 0x4079142: eventloop_iteration (libxl_event.c:1371)
==8655==    by 0x40799BB: libxl_event_wait (libxl_event.c:1396)
==8655==    by 0x805CC67: create_domain (xl_cmdimpl.c:1698)
==8655==    by 0x805E001: main_create (xl_cmdimpl.c:3986)
==8655==    by 0x804D43D: main (xl.c:285)


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

stubdom/grub/kexec.c

@@ -137,6 +137,10 @@ void kexec(void *kernel, long kernel_size, void *module, long module_size, char
     dom = xc_dom_allocate(xc_handle, cmdline, features);
     dom->allocate = kexec_allocate;
 
+    /* We are using guest owned memory, therefore no limits. */
+    xc_dom_kernel_max_size(dom, 0);
+    xc_dom_ramdisk_max_size(dom, 0);
+
     dom->kernel_blob = kernel;
     dom->kernel_size = kernel_size;