Add migration to reset custom pod specs

awx/main/migrations/0127_reset_pod_spec_override.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.2.16 on 2021-02-15 22:02
+
+from django.db import migrations
+
+def reset_pod_specs(apps, schema_editor):
+    InstanceGroup = apps.get_model('main', 'InstanceGroup')
+    InstanceGroup.objects.update(pod_spec_override="")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0126_executionenvironment_container_options'),
+    ]
+
+    operations = [
+        migrations.RunPython(reset_pod_specs)
+    ]