[libxslt] Fix memory leak in EXSLT functions error path

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 00b327b6ca85a64ce9bf521a04a6d1ca84f21f82
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Tue Feb 12 02:45:50 2019 +0100

    Fix memory leak in EXSLT functions error path

 libexslt/functions.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/libexslt/functions.c b/libexslt/functions.c
index 60056717..075e2366 100644
--- a/libexslt/functions.c
+++ b/libexslt/functions.c
@@ -476,6 +476,7 @@ exsltFuncFunctionFunction (xmlXPathParserContextPtr ctxt, int nargs) {
                         "executing a function\n",
                         ctxt->context->functionURI, ctxt->context->function);
        xmlFreeNode(fake);
+        xmlXPathFreeObject(ret);
        goto error;
     }
     xmlFreeNode(fake);