[libxml2] Fix a couple of return without value

[Daniel Veillard <veillard src gnome org>]

commit 9ca816b3a64e7b1bada7baa2cbc09e8937b38215
Author: Jüri Aedla <aedla chromium org>
Date:   Tue Apr 16 22:00:13 2013 +0800

    Fix a couple of return without value
    
    Error introduced in previous commit !

 parser.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/parser.c b/parser.c
index b9344b2..ee429f3 100644
--- a/parser.c
+++ b/parser.c
@@ -7784,7 +7784,7 @@ xmlParseStringEntityRef(xmlParserCtxtPtr ctxt, const xmlChar ** str) {
     }
     if (ctxt->instate == XML_PARSER_EOF) {
        xmlFree(name);
-       return;
+       return(NULL);
     }
 
     /*
@@ -8189,7 +8189,7 @@ xmlParseStringPEReference(xmlParserCtxtPtr ctxt, const xmlChar **str) {
        entity = ctxt->sax->getParameterEntity(ctxt->userData, name);
     if (ctxt->instate == XML_PARSER_EOF) {
        xmlFree(name);
-       return;
+       return(NULL);
     }
     if (entity == NULL) {
        /*