[1.5.x] Fixed #14264 -- Ensured settings.configure configures logging

Thanks Matt McDonald for the patch.
Backport of 34162698c from master.

django/conf/__init__.py

@@ -83,6 +83,7 @@ class LazySettings(LazyObject):
         for name, value in options.items():
             setattr(holder, name, value)
         self._wrapped = holder
+        self._configure_logging()
 
     @property
     def configured(self):

tests/regressiontests/logging_tests/tests.py

@@ -4,7 +4,7 @@ import copy
 import logging
 import warnings
 
-from django.conf import compat_patch_logging_config
+from django.conf import compat_patch_logging_config, LazySettings
 from django.core import mail
 from django.test import TestCase, RequestFactory
 from django.test.utils import override_settings
@@ -302,3 +302,20 @@ class SettingsConfigTest(AdminScriptTestCase):
         out, err = self.run_manage(['validate'])
         self.assertNoOutput(err)
         self.assertOutput(out, "0 errors found")
+
+
+def dictConfig(config):
+    dictConfig.called = True
+dictConfig.called = False
+
+
+class SettingsConfigureLogging(TestCase):
+    """
+    Test that calling settings.configure() initializes the logging
+    configuration.
+    """
+    def test_configure_initializes_logging(self):
+        settings = LazySettings()
+        settings.configure(
+            LOGGING_CONFIG='regressiontests.logging_tests.tests.dictConfig')
+        self.assertTrue(dictConfig.called)