Add migrations as a result of 2to3 converting choices to a list

After running 2to3 the choices defined for the `ExportJob.status` and
`Instance.itree_region_default` fields were wrapped with a call to `list()`.
This resulted in the order of the choices changing. Any change to the choices
defined for a field requires a migration.

Author: jwalgran

opentreemap/exporter/migrations/0002_exportjob_status_choices_to_list.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.17 on 2020-01-08 19:01
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('exporter', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='exportjob',
+            name='status',
+            field=models.IntegerField(choices=[(-1, 'Something went wrong with your export.'), (0, 'Pending'), (1, 'Query returned no trees or planting sites.'), (2, 'User has no permissions on this model'), (3, 'Ready')], default=0),
+        ),
+    ]

opentreemap/treemap/migrations/0047_instance_itree_region_default_choices_to_list.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.17 on 2020-01-08 19:01
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('treemap', '0046_auto_20170907_0937'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='instance',
+            name='itree_region_default',
+            field=models.CharField(blank=True, choices=[('CaNCCoJBK', 'Northern California Coast'), ('CenFlaXXX', 'Central Florida'), ('GulfCoCHS', 'Coastal Plain'), ('InlEmpCLM', 'Inland Empire'), ('InlValMOD', 'Inland Valleys'), ('InterWABQ', 'Interior West'), ('LoMidWXXX', 'Lower Midwest'), ('MidWstMSP', 'Midwest'), ('NMtnPrFNL', 'North'), ('NoEastXXX', 'Northeast'), ('PacfNWLOG', 'Pacific Northwest'), ('PiedmtCLT', 'South'), ('SoCalCSMA', 'Southern California Coast'), ('SWDsrtGDL', 'Southwest Desert'), ('TpIntWBOI', 'Temperate Interior West'), ('TropicPacXXX', 'Tropical')], max_length=20, null=True),
+        ),
+    ]