Workaround Django bug to work with be@latin locale

Monkey patch locales, workaround for
https://code.djangoproject.com/ticket/24063

weblate/lang/__init__.py

+# -*- coding: utf-8 -*-
+#
+# Copyright © 2012 - 2014 Michal Čihař <michal@cihar.com>
+#
+# This file is part of Weblate <http://weblate.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 3 of the License, or
+# (at your option) any later version.
+#
+# 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/>.
+#
+
+import django.utils.translation.trans_real
+import re
+
+# Monkey patch locales, workaround for
+# https://code.djangoproject.com/ticket/24063
+django.utils.translation.trans_real.language_code_re = re.compile(
+    r'^[a-z]{1,8}(?:-[a-z0-9]{1,8})*(?:@[a-z0-9]{1,20})?$', re.IGNORECASE
+)