add host variable dash fix as a migration

awx/main/migrations/0033_v303_v245_host_variable_fix.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+from awx.main.migrations import _migration_utils as migration_utils
+
+
+def update_dashed_host_variables(apps, schema_editor):
+    Host = apps.get_model('main', 'Host')
+    for host in Host.objects.filter(variables='---'):
+        host.variables = ''
+        host.save()
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0032_v302_credential_permissions_update'),
+    ]
+
+    operations = [
+        migrations.RunPython(migration_utils.set_current_apps_for_migrations),
+        migrations.RunPython(update_dashed_host_variables),
+    ]