[libxml2] Fix memory leak in xmlRelaxNGParseData

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 483de2c21dc25aaad9ca027a0052d8f48415cac8
Author: David King <amigadave amigadave com>
Date:   Wed Jul 14 15:31:55 2021 +0100

    Fix memory leak in xmlRelaxNGParseData
    
    Found by Coverity.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1938806

 relaxng.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/relaxng.c b/relaxng.c
index 0ceecb58..04cb55ec 100644
--- a/relaxng.c
+++ b/relaxng.c
@@ -3654,6 +3654,7 @@ xmlRelaxNGParseData(xmlRelaxNGParserCtxtPtr ctxt, xmlNodePtr node)
 
     def = xmlRelaxNGNewDefine(ctxt, node);
     if (def == NULL) {
+        xmlFree(library);
         xmlFree(type);
         return (NULL);
     }