Change slightly the PostgreSQL backend compatibility code.

cachalot/apps.py

@@ -1,4 +1,3 @@
-from django import VERSION as django_version
 from django.apps import AppConfig
 from django.conf import settings
 from django.core.checks import register, Tags, Error, Warning
@@ -8,8 +7,10 @@
 
 VALID_DATABASE_ENGINES = {
     'django.db.backends.sqlite3',
-    'django.db.backends.postgresql_psycopg2',
+    'django.db.backends.postgresql',
     'django.db.backends.mysql',
+    # TODO: Remove when we drop Django 1.8 support.
+    'django.db.backends.postgresql_psycopg2',
 
     # GeoDjango
     'django.contrib.gis.db.backends.spatialite',
@@ -23,9 +24,6 @@
     'transaction_hooks.backends.mysql',
 }
 
-if django_version[:2] >= (1, 9):
-    VALID_DATABASE_ENGINES.add('django.db.backends.postgresql')
-
 
 VALID_CACHE_BACKENDS = {
     'django.core.cache.backends.dummy.DummyCache',

settings.py

@@ -3,19 +3,15 @@
 from __future__ import unicode_literals
 import os
 
-
-if django_version[:2] >= (1, 9):
-    POSTGRES_ENGINE = 'django.db.backends.postgresql'
-else:
-    POSTGRES_ENGINE = 'django.db.backends.postgresql_psycopg2'
+from django import VERSION as django_version
 
 DATABASES = {
     'sqlite3': {
         'ENGINE': 'django.db.backends.sqlite3',
         'NAME': 'cachalot.sqlite3',
     },
     'postgresql': {
-        'ENGINE': POSTGRES_ENGINE,
+        'ENGINE': 'django.db.backends.postgresql',
         'NAME': 'cachalot',
         'USER': 'cachalot',
     },
@@ -25,6 +21,8 @@
         'USER': 'root',
     },
 }
+if django_version[:2] == (1, 8):
+    DATABASES['postgresql']['ENGINE'] = 'django.db.backends.postgresql_psycopg2'
 for alias in DATABASES:
     test_db_name = 'test_' + DATABASES[alias]['NAME']
     DATABASES[alias]['TEST'] = {'NAME': test_db_name}