at migration time, validate ldap group type params

* Previously, we have logic in the API to ensure that ldap group type
params, when changed, align with ldap group type Class init
expectations. However, we did not have this logic in the migrations.
This PR adds the validation check to migrations.

awx/conf/migrations/0006_v331_ldap_group_type.py

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+# AWX
+from awx.conf.migrations._ldap_group_type import fill_ldap_group_type_params
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('conf', '0005_v330_rename_two_session_settings'),
+    ]
+
+    operations = [
+        migrations.RunPython(fill_ldap_group_type_params),
+    ]

awx/conf/migrations/_ldap_group_type.py

@@ -0,0 +1,30 @@
+
+import inspect
+
+from django.conf import settings
+from django.utils.timezone import now
+
+
+def fill_ldap_group_type_params(apps, schema_editor):
+    group_type = settings.AUTH_LDAP_GROUP_TYPE
+    Setting = apps.get_model('conf', 'Setting')
+
+    group_type_params = {'name_attr': 'cn', 'member_attr': 'member'}
+    qs = Setting.objects.filter(key='AUTH_LDAP_GROUP_TYPE_PARAMS')
+    entry = None
+    if qs.exists():
+        entry = qs[0]
+        group_type_params = entry.value
+    else:
+        entry = Setting(key='AUTH_LDAP_GROUP_TYPE_PARAMS',
+                        value=group_type_params,
+                        created=now(),
+                        modified=now())
+
+    init_attrs = set(inspect.getargspec(group_type.__init__).args[1:])
+    for k in group_type_params.keys():
+        if k not in init_attrs:
+            del group_type_params[k]
+
+    entry.value = group_type_params
+    entry.save()