Title: Removing a previously set custom attribute for a contact did not work as intented
Level: 1
Component: wato
Compatible: compat
Version: 1.2.8b1
Date: 1453457638
Class: fix

The mechanism resetting a custom attribute to its default value was not working properly.
In the GUI you could see that the attribute was correctly unset.
However, the configuration for the monitoring core still used the old configured value..
This has been fixed.
