WARN_ON_DELETE turns on or off the warning dialog when
working with relations.
---->(WARN_ON_DELETE)----+----(:ON)----+---->
| |
+----(:OFF)---+
The following options are available to set this switch.
- :ON - turns the warning dialog on when in delete mode.
- :OFF - turns the warning dialog off when in delete mode.
This switch is used to turn on or off the "Warning on Delete"
dialog.