pull up r24539 from trunk

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 r24539 | hartmans | 2010-11-30 17:46:54 -0500 (Tue, 30 Nov 2010) | 7 lines

 ticket: 6828
 Subject: Install kadm5_hook_plugin.h
 target_version: 1.9
 tags: pullup

 Install the kadm5 hook plugin header

https://github.com/krb5/krb5/commit/adf66a9a64118a7b8d512ea8438a97a467c8f5db
Commit By: tlyu
Revision: 24551
Changed Files:
U   branches/krb5-1-9/src/include/Makefile.in