pull up r23716 from trunk

pull up r23716 from trunk

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 r23716 | ghudson | 2010-02-11 11:07:08 -0500 (Thu, 11 Feb 2010) | 15 lines

 ticket: 6660
 subject: Minimal support for updating history key
 target_version: 1.8
 tags: pullup

 Add minimal support for re-randomizing the history key:

 * cpw -randkey kadmin/history now works, but creates only one key.
 * cpw -randkey -keepold kadmin/history still fails.
 * libkadm5 no longer caches the history key.  Performance impact
   is minimal since password changes are not common.
 * randkey no longer checks the newly randomized key against old keys,
   and the disabled code to do so in setkey/setv4key is gone, so now
   only kadm5_chpass_principal_3 accesses the password history.

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ticket: 6660
version_fixed: 1.8
status: resolved

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-8@23721 dc483132-0cff-0310-8789-dd5450dbe970