libmm-glib: use g_list_copy_deep for deep copying a GList

libmm-glib/mm-modem-messaging.c

@@ -273,8 +273,7 @@ mm_modem_messaging_list_finish (MMModemMessaging *self,
 
     /* The list we got, including the objects within, is owned by the async result;
      * so we'll make sure we return a new list */
-    g_list_foreach (list, (GFunc)g_object_ref, NULL);
-    return g_list_copy (list);
+    return g_list_copy_deep (list, (GCopyFunc)g_object_ref, NULL);
 }
 
 static void create_next_sms (ListSmsContext *ctx);

libmm-glib/mm-modem-voice.c

@@ -138,8 +138,7 @@ mm_modem_voice_list_calls_finish (MMModemVoice *self,
 
     /* The list we got, including the objects within, is owned by the async result;
      * so we'll make sure we return a new list */
-    g_list_foreach (list, (GFunc)g_object_ref, NULL);
-    return g_list_copy (list);
+    return g_list_copy_deep (list, (GCopyFunc)g_object_ref, NULL);
 }
 
 static void create_next_call (ListCallsContext *ctx);

libmm-glib/mm-modem.c

@@ -1806,8 +1806,7 @@ mm_modem_list_bearers_finish (MMModem *self,
 
     /* The list we got, including the objects within, is owned by the async result;
      * so we'll make sure we return a new list */
-    g_list_foreach (list, (GFunc)g_object_ref, NULL);
-    return g_list_copy (list);
+    return g_list_copy_deep (list, (GCopyFunc)g_object_ref, NULL);
 }
 
 static void create_next_bearer (ListBearersContext *ctx);