qapi: g_hash_table_find() instead of GHashTableIter.

GHashTableIter was first introduced in glib 2.16.
This patch removes it in favor of older g_hash_table_find()
for better compatibility with RHEL5.
Signed-off-by: NNODA, Kai <nodakai@gmail.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

qapi/qmp-input-visitor.c

@@ -87,20 +87,29 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
     qiv->nb_stack++;
 }
 
+/** Only for qmp_input_pop. */
+static gboolean always_true(gpointer key, gpointer val, gpointer user_pkey)
+{
+    *(const char **)user_pkey = (const char *)key;
+    return TRUE;
+}
+
 static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
 {
-    GHashTableIter iter;
-    gpointer key;
+    assert(qiv->nb_stack > 0);
 
-    if (qiv->strict && qiv->stack[qiv->nb_stack - 1].h) {
-        g_hash_table_iter_init(&iter, qiv->stack[qiv->nb_stack - 1].h);
-        if (g_hash_table_iter_next(&iter, &key, NULL)) {
-            error_set(errp, QERR_QMP_EXTRA_MEMBER, (char *) key);
+    if (qiv->strict) {
+        GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
+        if (top_ht) {
+            if (g_hash_table_size(top_ht)) {
+                const char *key;
+                g_hash_table_find(top_ht, always_true, &key);
+                error_set(errp, QERR_QMP_EXTRA_MEMBER, key);
+            }
+            g_hash_table_unref(top_ht);
         }
-        g_hash_table_unref(qiv->stack[qiv->nb_stack - 1].h);
     }
 
-    assert(qiv->nb_stack > 0);
     qiv->nb_stack--;
 }