remove job to jt allow_simultaneous dependency

* Foreshadowing of what's to come with the task manager. When deciding
on what job to run in our task manager, we can't depend on job template
fields. Otherwise, this would cost us a query.

awx/main/migrations/0037_job_allow_simultaneous.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0036_v310_remove_tower_settings'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='job',
+            name='allow_simultaneous',
+            field=models.BooleanField(default=False),
+        ),
+    ]