Merge pull request #2667 from FroggyFlox/2666-use_for_related_fields-…

…is-deprecated-in-Django-2.0

Set `Meta.base_manager_name` on 'storageadmin.Disk' #2666

src/rockstor/storageadmin/models/disk.py

@@ -31,8 +31,6 @@
 class AttachedManager(models.Manager):
     """Manager subclass to return only attached disks"""
 
-    use_for_related_fields = True
-
     def attached(self):
         # Return default queryset after excluding name="detached-*" items.
         # Alternative lookup type __regex=r'^detached-'
@@ -151,3 +149,4 @@ def target_name(self, *args, **kwargs):
 
     class Meta:
         app_label = "storageadmin"
+        base_manager_name = "attached"