Fix some issues syncing playbooks

* Build a list of playbooks and store it in the database at sync time
* Fix an issue running playbook sync on jobs for scan jobs
* Remove a TODO that was unneeded

awx/main/migrations/0044_v310_project_playbook_files.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import jsonfield.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0043_v310_scm_revision'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='project',
+            name='playbook_files',
+            field=jsonfield.fields.JSONField(default=[], help_text='List of playbooks found in the project', verbose_name='Playbook Files', editable=False, blank=True),
+        ),
+    ]