Remove dj-database-url, django-environ includes the same thing

requirements/prod.txt

@@ -89,8 +89,6 @@ defusedxml==0.4.1 \
 dennis==0.7 \
     --hash=sha256:e9e925c0097c6f5eb7716e50ca57155ed1f670f0fa72a661053198c1890a02f5 \
     --hash=sha256:fde267aeb03a8d49e3341e7f71a228c6748dce43b5c00f65581780d99b70b2d9
-dj-database-url==0.2.2 \
-    --hash=sha256:492a7294b85ad8ac1b13be0b7337f381d2d44c4da185f289ab7c26dd765ef6cb
 django-aesfield==0.1.2 \
     --hash=sha256:b77932c67dd42f01a119133de1fa88effb2c4d97ab9039d9c95ae96049fadd5f
 django-babel==0.5.1 \

src/olympia/lib/settings_base.py

@@ -6,11 +6,13 @@ import logging
 import os
 import socket
 
-import dj_database_url
 from django.utils.functional import lazy
 from django.core.urlresolvers import reverse_lazy
+import environ
 from heka.config import client_from_dict_config
 
+env = environ.Env()
+
 ALLOWED_HOSTS = [
     '.allizom.org',
     '.mozilla.org',
@@ -87,9 +89,9 @@ CORS_ENDPOINT_OVERRIDES = [
     }),
 ]
 
-DATABASE_URL = os.environ.get('DATABASE_URL',
-                              'mysql://root:@localhost/olympia')
-DATABASES = {'default': dj_database_url.parse(DATABASE_URL)}
+DATABASES = {
+    'default': env.db(default='mysql://root:@localhost/olympia')
+}
 DATABASES['default']['OPTIONS'] = {'sql_mode': 'STRICT_ALL_TABLES'}
 DATABASES['default']['TEST_CHARSET'] = 'utf8'
 DATABASES['default']['TEST_COLLATION'] = 'utf8_general_ci'