ipa-kdb: fix gcc complaints
    
    In file included from /usr/include/string.h:519,
                     from /usr/include/lber.h:30,
                     from /usr/include/ldap.h:30,
                     from ipa_kdb.h:37,
                     from ipa_kdb_mspac.c:26:
    In function 'strncpy',
        inlined from 'get_server_netbios_name' at ipa_kdb_mspac.c:2358:5,
        inlined from 'ipadb_reinit_mspac' at ipa_kdb_mspac.c:2813:39:
    /usr/include/bits/string_fortified.h:91:10: warning: 'strncpy' specified bound 255 equals destination size [-Wstringop-truncation]
       91 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
          |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
    Fixes: https://pagure.io/freeipa/issue/8585
    Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>