QCalendar: use LGPL like everything else, not GPL

Pointed out by Lars.

Change-Id: Idb8427d77b35c84eb3037703957cf7f93ea5f387
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/corelib/time/qcalendar.cpp

@@ -5,7 +5,7 @@
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
 **
-** $QT_BEGIN_LICENSE:GPL$
+** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
@@ -14,14 +14,24 @@
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 or (at your option) any later version
-** approved by the KDE Free Qt Foundation. The licenses are as published by
-** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
 ** included in the packaging of this file. Please review the following
 ** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **