[libxml2] Fix memory leak in xmlLoadEntityContent error path

[Nick Wellnhofer <nwellnhof src gnome org>]

commit ca2c91f139426f63646292da58a15a1511dccc0f
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Tue Jun 28 19:24:14 2022 +0200

    Fix memory leak in xmlLoadEntityContent error path
    
    Free the input stream if pushing it fails.
    
    Found by OSS-Fuzz.
    
    https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=43743

 parser.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/parser.c b/parser.c
index 0464a302..d278638d 100644
--- a/parser.c
+++ b/parser.c
@@ -8088,6 +8088,7 @@ xmlLoadEntityContent(xmlParserCtxtPtr ctxt, xmlEntityPtr entity) {
      */
     if (xmlPushInput(ctxt, input) < 0) {
         xmlBufferFree(buf);
+       xmlFreeInputStream(input);
        return(-1);
     }