[libxml2] Couple of Missing Null checks

[Daniel Veillard <veillard src gnome org>]

commit 658b86c0eaacefb0999873efb883c7e50c628d18
Author: Gaurav Gupta <g gupta samsung com>
Date:   Thu Aug 7 11:19:03 2014 +0800

    Couple of Missing Null checks
    
    For https://bugzilla.gnome.org/show_bug.cgi?id=734328
    
    Missing Null check could cause crash, if a pointer is dereferenced.
    
    Found problem at two places in valid.c

 valid.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/valid.c b/valid.c
index 1e03a7c..409aa81 100644
--- a/valid.c
+++ b/valid.c
@@ -1798,6 +1798,7 @@ xmlCopyEnumeration(xmlEnumerationPtr cur) {
 
     if (cur == NULL) return(NULL);
     ret = xmlCreateEnumeration((xmlChar *) cur->name);
+    if (ret == NULL) return(NULL);
 
     if (cur->next != NULL) ret->next = xmlCopyEnumeration(cur->next);
     else ret->next = NULL;
@@ -6996,6 +6997,9 @@ xmlValidGetValidElements(xmlNode *prev, xmlNode *next, const xmlChar **names,
      * Creates a dummy node and insert it into the tree
      */
     test_node = xmlNewDocNode (ref_node->doc, NULL, BAD_CAST "<!dummy?>", NULL);
+    if (test_node == NULL)
+        return(-1);
+
     test_node->parent = parent;
     test_node->prev = prev;
     test_node->next = next;