[java-atk-wrapper] Add missing reference release

[Samuel Thibault <sthibaul src gnome org>]

commit 472b456188ae7e094792e849fd39f5cc40615d13
Author: Samuel Thibault <samuel thibault ens-lyon org>
Date:   Wed Jul 10 23:51:46 2019 +0200

    Add missing reference release

 jni/src/jawobject.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/jni/src/jawobject.c b/jni/src/jawobject.c
index 7a32240..d8a6b39 100644
--- a/jni/src/jawobject.c
+++ b/jni/src/jawobject.c
@@ -236,6 +236,7 @@ jaw_object_set_parent(AtkObject *atk_obj, AtkObject *parent)
   JawObject *jaw_par = JAW_OBJECT(parent);
   jobject pa = (*jniEnv)->NewGlobalRef(jniEnv, jaw_par->acc_context);
   if (!pa) {
+      (*jniEnv)->DeleteGlobalRef(jniEnv, ac);
       return;
   }