Forgot to add this file, needed for interfaces to build

Ups...

interfaces/interfaces_debug.h

@@ -0,0 +1,28 @@
+/**
+ * Copyright 2014 Alejandro Fiestas Olivares <afiestas@kde.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License or (at your option) version 3 or any later version
+ * accepted by the membership of KDE e.V. (or its successor approved
+ * by the membership of KDE e.V.), which shall act as a proxy
+ * defined in Section 14 of version 3 of the license.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef KDECONNECT_INTERFACE_DEBUG_H
+#define KDECONNECT_INTERFACE_DEBUG_H
+
+#include <QLoggingCategory>
+
+Q_DECLARE_LOGGING_CATEGORY(KDECONNECT_INTERFACES)
+
+#endif //KDECONNECT_INTERFACE_DEBUG_H