fix(db): fixed django migration

With direct SQL, we can guarantee that the statements will be executed
on all systems that did not yet apply migration 0009.

In the old version, migration failed on systems that still had unique
varchar(255) database fields.

api/desecapi/migrations/0009_auto_20161201_1548.py

@@ -12,14 +12,12 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
-        migrations.AlterField(
-            model_name='domain',
-            name='name',
-            field=models.CharField(max_length=191, unique=True),
+        migrations.RunSQL(
+            [('alter table desecapi_user change column email email varchar(191) not null;', None)],
+            migrations.RunSQL.noop
         ),
-        migrations.AlterField(
-            model_name='user',
-            name='email',
-            field=models.EmailField(max_length=191, unique=True, verbose_name='email address'),
+        migrations.RunSQL(
+            [('alter table desecapi_domain change column name name varchar(191) not null;', None)],
+            migrations.RunSQL.noop
         ),
     ]