Cleaning up python3 migrations.

I think when I inadvertently removed the 0005-* automatic migration
that broke the tests and subsequent migrations. I'm putting everything
back into place in a form athat should restore the tests.

gracedb/superevents/migrations/0005_auto_20190919_1957.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.23 on 2019-09-19 19:57
+# Note from Tanner:
+# This was auto-generated after moving to Python 3, with no changes to the
+# actual models. See the commit message for more details.
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('superevents', '0004_populate_voevent_fields'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='log',
+            name='filename',
+            field=models.CharField(blank=True, default='', max_length=100),
+        ),
+        migrations.AlterField(
+            model_name='signoff',
+            name='instrument',
+            field=models.CharField(blank=True, choices=[('H1', 'LHO'), ('L1', 'LLO'), ('V1', 'Virgo')], max_length=2),
+        ),
+        migrations.AlterField(
+            model_name='signoff',
+            name='signoff_type',
+            field=models.CharField(choices=[('OP', 'operator'), ('ADV', 'advocate')], max_length=3),
+        ),
+        migrations.AlterField(
+            model_name='signoff',
+            name='status',
+            field=models.CharField(choices=[('OK', 'OKAY'), ('NO', 'NOT OKAY')], max_length=2),
+        ),
+        migrations.AlterField(
+            model_name='superevent',
+            name='category',
+            field=models.CharField(choices=[('P', 'Production'), ('T', 'Test'), ('M', 'MDC')], default='P', max_length=1),
+        ),
+        migrations.AlterField(
+            model_name='voevent',
+            name='filename',
+            field=models.CharField(blank=True, default='', editable=False, max_length=100),
+        ),
+        migrations.AlterField(
+            model_name='voevent',
+            name='ivorn',
+            field=models.CharField(blank=True, default='', editable=False, max_length=200),
+        ),
+        migrations.AlterField(
+            model_name='voevent',
+            name='voevent_type',
+            field=models.CharField(choices=[('PR', 'preliminary'), ('IN', 'initial'), ('UP', 'update'), ('RE', 'retraction')], max_length=2),
+        ),
+    ]

gracedb/superevents/migrations/0006_add_coinc_far_and_em_type.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.20 on 2019-05-15 18:07
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('superevents', '0005_auto_20190919_1957'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='Superevent',
+            name='coinc_far',
+            field=models.FloatField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='Superevent',
+            name='em_type',
+            field=models.CharField(null=True, blank=True, max_length=100),
+        ),
+    ]

gracedb/superevents/migrations/0007_add_raven_voevent_fields.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.20 on 2019-05-15 18:07
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('superevents', '0006_add_coinc_far_and_em_type'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='voevent',
+            name='raven_coinc',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='combined_skymap_filename',
+            field=models.CharField(blank=True, default=None, max_length=100, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='ext_gcn',
+            field=models.CharField(blank=True, default=None, max_length=100, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='ext_pipeline',
+            field=models.CharField(blank=True, default=None, max_length=100, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='ext_search',
+            field=models.CharField(blank=True, default=None, max_length=100, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='time_coinc_far',
+            field=models.FloatField(blank=True, default=None, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='space_coinc_far',
+            field=models.FloatField(blank=True, default=None, null=True),
+        ),
+        migrations.AddField(
+            model_name='voevent',
+            name='delta_t',
+            field=models.FloatField(blank=True, default=None, null=True),
+        ),
+    ]