Apply behaviour change fix from upstream for previous XPath change.

BUG=58731
TEST=NONE

Review URL: http://codereview.chromium.org/4027006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63572 0039d316-1c4b-4281-b951-d872f2087c98
xmlXPathNextSelf(xmlXPathParserContextPtr ctxt, xmlNodePtr cur) {
    if ((ctxt == NULL) || (ctxt->context == NULL)) return(NULL);
    if (cur == NULL)
        return(ctxt->context->node);
    return(NULL);
}

xmlXPathNextSelf(xmlXPathParserContextPtr ctxt, xmlNodePtr cur) {
    if ((ctxt == NULL) || (ctxt->context == NULL)) return(NULL);
    if (cur == NULL)
        return(ctxt->context->node);
    return(NULL);
}
