(ITS#4752) back-config Adds are not atomic

Full_Name: Howard Chu Version: HEAD/23/24 OS: URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (76.168.84.21) Submitted by: hyc

When LDAPAdding various types of entries under cn=config, failures in some later portion of the entry will cause the operation to fail but anything already set remains set. The current approach of using check_vals to validate before doing the main processing is inadequate. It may be possible to extend the current pre-check approach, otherwise we'll need to do something like define destructors for everything.