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>