Update Django and gvacommon dependencies

This commit updates the Django dependency version to 1.9.2 and gvacommon
to 0.3.0 that provides gvacommon.settings_utils.get_env_variable. The
gnuviechadmin.settings.base module now uses this implementation instead
of an own copy and the corresponding test has been removed too.

gnuviechadmin/gnuviechadmin/settings/base.py

@@ -5,30 +5,12 @@ Common settings and globals.
 
 """
 
-from os import environ
 from os.path import abspath, basename, dirname, join, normpath
 from sys import path
 
-# Normally you should not import ANYTHING from Django directly
-# into your settings, but ImproperlyConfigured is an exception.
-from django.core.exceptions import ImproperlyConfigured
 from django.contrib.messages import constants as messages
 
-
-def get_env_variable(var_name):
-    """
-    Get a setting from an environment variable.
-
-    :param str var_name: variable name
-    :raises ImproperlyConfigured: if the environment setting is not defined
-    :return: environment setting value
-    :rtype: str
-    """
-    try:
-        return environ[var_name]
-    except KeyError:
-        error_msg = "Set the %s environment variable" % var_name
-        raise ImproperlyConfigured(error_msg)
+from gvacommon.settings_utils import get_env_variable
 
 
 # ######### PATH CONFIGURATION

gnuviechadmin/gnuviechadmin/tests/test_settings.py

@@ -1,23 +0,0 @@
-# -*- python -*-
-# -*- coding: utf-8 -*-
-import os
-from unittest import TestCase
-
-from django.core.exceptions import ImproperlyConfigured
-
-from gnuviechadmin.settings.base import get_env_variable
-
-
-class GetEnvVariableTest(TestCase):
-
-    def test_get_existing_env_variable(self):
-        os.environ['testvariable'] = 'myvalue'
-        self.assertEqual(get_env_variable('testvariable'), 'myvalue')
-
-    def test_get_missing_env_variable(self):
-        if 'missingvariable' in os.environ:
-            del os.environ['missingvariable']
-        with self.assertRaises(ImproperlyConfigured) as e:
-            get_env_variable('missingvariable')
-        self.assertEqual(
-            str(e.exception), 'Set the missingvariable environment variable')