[libxml2] Adding a check in case of allocation error

[Daniel Veillard <veillard src gnome org>]

commit 6d753994b9cdfccec5d0075d5685cae9ad06bec1
Author: Gaurav Gupta <g gupta samsung com>
Date:   Mon Jul 14 16:01:10 2014 +0800

    Adding a check in case of allocation error
    
    For https://bugzilla.gnome.org/show_bug.cgi?id=733043
    
    There is missing Null condition in xmlRelaxNGValidateInterleave of
    relaxng.c
    Dereferencing it may cause a crash.

 relaxng.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/relaxng.c b/relaxng.c
index f34dc14..1ba4fba 100644
--- a/relaxng.c
+++ b/relaxng.c
@@ -9419,6 +9419,10 @@ xmlRelaxNGValidateInterleave(xmlRelaxNGValidCtxtPtr ctxt,
     oldstate = ctxt->state;
     for (i = 0; i < nbgroups; i++) {
         ctxt->state = xmlRelaxNGCopyValidState(ctxt, oldstate);
+       if (ctxt->state == NULL) {
+           ret = -1;
+           break;
+       }
         group = partitions->groups[i];
         if (lasts[i] != NULL) {
             last = lasts[i]->next;