Arruma problema da recriação das constraints

Signed-off-by: Luciano Almeida <lucianoalmeida@interlegis.leg.br>

sapl/base/migrations/0002_auto_20170331_1900.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.12 on 2017-03-31 19:00
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('base', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Argumento',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('argumento', models.CharField(max_length=50, verbose_name='Argumento')),
+            ],
+            options={
+                'verbose_name': 'Argumento da constraint',
+                'verbose_name_plural': 'Argumentos da constraint',
+            },
+        ),
+        migrations.CreateModel(
+            name='Constraint',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('nome_tabela', models.CharField(max_length=50, verbose_name='Nome da tabela')),
+                ('nome_constraint', models.CharField(max_length=100, verbose_name='Nome da constraint')),
+                ('nome_model', models.CharField(max_length=50, verbose_name='Nome da model')),
+                ('tipo_constraint', models.CharField(max_length=50, verbose_name='Tipo da constraint')),
+            ],
+            options={
+                'verbose_name': 'Constraint removida',
+                'verbose_name_plural': 'Constraints removidas',
+            },
+        ),
+        migrations.AddField(
+            model_name='problemamigracao',
+            name='eh_importante',
+            field=models.BooleanField(default=False, verbose_name='É importante?'),
+        ),
+        migrations.AddField(
+            model_name='argumento',
+            name='constraint',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='base.Constraint'),
+        ),
+    ]

sapl/legacy/migration.py

@@ -253,8 +253,10 @@ def recreate_constraints():
         if con.tipo_constraint == 'unique_together':
             nome_tabela = con.nome_tabela
             nome_constraint = con.nome_constraint
-            model = ContentType.objects.get(
+            # Pegando explicitamente o primeiro valor do filter,
-                model=con.nome_model.lower()).model_class()
+            # pois pode ser que haja mais de uma ocorrência
+            model = ContentType.objects.filter(
+                model=con.nome_model.lower())[0].model_class()
             args = [a.argumento for a in con.argumento_set.all()]
             for i in range(len(args)):
                 if isinstance(model._meta.get_field(args[i]),