s4 upgradeprovision: Adapt the list of attribute modified

s4 upgradeprovision: Adapt the list of attribute modified

* isMemberOfPartialAttributeSet is now allowed to be deleted (on schema
 objects)
* attributeDisplayNames is now allowed to be added and modified (used on
  display specifiers)
* spnMapping is now allowed to be altered on Directory Service objects
* minPwdAge is now modified if the previous value was 0

We issue a clear information about the userControl attribute for
administrator to invite the user to modify himself the value.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>